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Field evaluation of a smartphone-based electronic reader of rapid dual HIV and syphilis point-of-care immunoassays
Abstract
Objective
Electronic (E) devices read and quantify lateral flow-based rapid tests, providing a novel approach to assay interpretation. We evaluated the performance of one E-reader for two dual HIV and syphilis immunoassays.
Methods
We enrolled men who have sex with men and transgender women >18 years of age seeking medical services at an STD clinic in Lima, Peru, between October 2016 and April 2017. Venous blood was tested using two dual HIV and syphilis antibody immunoassays (SD BIOLINE HIV/Syphilis Duo, Republic of Korea, and First Response HIV 1+2/Syphilis Combo, India). Reference testing included a fourth-generation ELISA for HIV antibodies and use of the Treponema pallidum particle agglutination assay for syphilis antibodies. Trained clinic staff visually inspected the immunoassay results, after which the immunoassays were read by the HRDR-200 E-reader (Cellmic, USA), an optomechanical smartphone attachment. We calculated the concordance of the E-reader with visual inspection, as well as the sensitivity of both rapid immunoassays, in detecting HIV and T. pallidum antibodies.
Results
On reference testing of 283 participant specimens, 34% had HIV antibodies and 46% had T. pallidum antibodies. Using First Response, the concordance of the E-reader with visual inspection was 97% (95% CI 94% to 99%) for T. pallidum and 97% (95% CI 95% to 99%) for HIV antibodies. Using SD BIOLINE, the concordance of the E-reader with visual inspection was 97% (95% CI 94% to 99%) for T. pallidum and 99% (95% CI 98% to 99%) for HIV antibodies. For both immunoassays, the sensitivity for HIV antibodies was 98% (95% CI 93% to 100%) and the sensitivity for T. pallidum antibodies was 81% (95% CI 73% to 87%).
Conclusions
E-reader results correlated well with visual inspection. The sensitivities of both rapid assays were comparable with past reports. Further evaluation of the E-reader is warranted to investigate its utility in data collection, monitoring and documentation of immunoassay results.
... 10,11 Of these, the First Response HIV1+2/Syphilis Combo Card Test was the first to be prequalified by the WHO in 2019, 12 and has been used in laboratory and field evaluations, clinical settings and surveys since then, with sensitivities and specificities of 80% -100%. 13,14,15 The National Department of Health (NDOH) in South Africa started introducing rapid dual HIV/syphilis testing for pregnant women in response to rising syphilis rates among pregnant women, the need for more frequent testing during pregnancy, and to delays in starting appropriate treatment that was associated with laboratory testing. 5 The NDOH is considering expanding rapid dual HIV/syphilis testing to other priority populations with respect to STIs and syphilis -MSM, transgender women (TGW), female sex workers (FSW) and people receiving pre-exposure prophylaxis. ...
Background: Dual HIV/syphilis testing may be an acceptable intervention to identify men with sexually transmitted infections (STIs) and at risk of HIV acquisition.
Objectives: We sought to determine the acceptability, and performance of dual HIV/syphilis testing among men attending voluntary medical male circumcision (VMMC) services at six public sector facilities in Gauteng.
Method: This was a cross-sectional study at VMMC facilities. Men ≥ 18 years were enrolled. The men had (1) a questionnaire administered, (2) on-site dual HIV/syphilis testing with First Response HIV1+2/Syphilis Combo Card Test by routine lay counsellors, and (3) a blood specimen collected for centralised laboratory testing for HIV and syphilis serology. We evaluated pre-test and post-test acceptability and performance compared to serological testing.
Results: Of the 679 men analysed (median age 32.1 years), 96.7% of HIV-negative men preferred testing for HIV and syphilis simultaneously. Of the 675 men tested for syphilis, 28 (4.7%) tested positive (past or recent). In the laboratory, 43/609 (7.1%) had syphilis infection detected, with 9/609 (1.5%) having recent syphilis. There was sub-optimal sensitivity for HIV detection (90.9%; 95% confidence interval [CI]: 88.5% – 93.3%), and for past/recent syphilis (55.8%; 95% CI: 51.9% – 59.8%), improving to 88.9% (95% CI: 86.4% – 91.4%) for recent syphilis. Specificities were > 99% for HIV and syphilis (past or recent). Post-test acceptability was 96.6% and willingness to pay for future testing was 86.1%.
Conclusion: Dual HIV/syphilis testing was acceptable but had sub-optimal sensitivity for HIV and syphilis. Syphilis detection was adequate for recent infection.
... Another study found a prototype SER capable of analyzing unprocessed liquid semen samples and providing users with a World Health Organization standard semen quality evaluation report with 98% accuracy [35]. Furthermore, other studies have shown prototype SERs capable of interpreting HIV rapid diagnostic test results with good accuracy and highlighted their capacity to capture real-time data [36,37]. Hence, coupled with recent advancements in smartphone computing, artificial intelligence, and open-source operating systems, SERs could be potential substitutes for bridging patient-health care provider barriers, and they could facilitate HIVST results reporting and active posttest counseling services through real-time data capturing. ...
Background
The need for strategies to encourage user-initiated reporting of results after HIV self-testing (HIVST) persists. Smartphone-based electronic readers (SERs) have been shown capable of reading diagnostics results accurately in point-of-care diagnostics and could bridge the current gaps between HIVST and linkage to care.
Objective
Our study aimed to assess the willingness of Chinese men who have sex with men (MSM) in the Jiangsu province to use an SER for HIVST through a web-based cross-sectional study.
Methods
From February to April 2020, we conducted a convenience web-based survey among Chinese MSM by using a pretested structured questionnaire. Survey items were adapted from previous HIVST feasibility studies and modified as required. Prior to answering reader-related questions, participants watched a video showcasing a prototype SER. Statistical analysis included descriptive analysis, chi-squared test, and multivariable logistic regression. P values less than .05 were deemed statistically significant.
Results
Of 692 participants, 369 (53.3%) were aged 26-40 years, 456 (65.9%) had ever self-tested for HIV, and 493 (71.2%) were willing to use an SER for HIVST. Approximately 98% (483/493) of the willing participants, 85.3% (459/538) of ever self-tested and never self-tested, and 40% (46/115) of unwilling participants reported that SERs would increase their HIVST frequency. Engaging in unprotected anal intercourse with regular partners compared to consistently using condoms (adjusted odds ratio [AOR] 3.04, 95% CI 1.19-7.74) increased the odds of willingness to use an SER for HIVST. Participants who had ever considered HIVST at home with a partner right before sex compared to those who had not (AOR 2.99, 95% CI 1.13-7.90) were also more willing to use an SER for HIVST. Playing receptive roles during anal intercourse compared to playing insertive roles (AOR 0.05, 95% CI 0.02-0.14) was associated with decreased odds of being willing to use an SER for HIVST. The majority of the participants (447/608, 73.5%) preferred to purchase readers from local Centers of Disease Control and Prevention offices and 51.2% (311/608) of the participants were willing to pay less than US $4.70 for a reader device.
Conclusions
The majority of the Chinese MSM, especially those with high sexual risk behaviors, were willing to use an SER for HIVST. Many MSM were also willing to self-test more frequently for HIV with an SER. Further research is needed to ascertain the diagnostic and real-time data-capturing capacity of prototype SERs during HIVST.
... An array of approaches have been piloted at small scales (n ≤ 283) and have shown good performance. However, most require a physical attachment such as a dongle (92-100% sensitivity, 97-100% specificity) 33 , a cradle 34 or a portable reader (97-98% sensitivity) 35 , which increases cost and complexity, and these are typically reliant on simple image analysis software. ...
Although deep learning algorithms show increasing promise for disease diagnosis, their use with rapid diagnostic tests performed in the field has not been extensively tested. Here we use deep learning to classify images of rapid human immunodeficiency virus (HIV) tests acquired in rural South Africa. Using newly developed image capture protocols with the Samsung SM-P585 tablet, 60 fieldworkers routinely collected images of HIV lateral flow tests. From a library of 11,374 images, deep learning algorithms were trained to classify tests as positive or negative. A pilot field study of the algorithms deployed as a mobile application demonstrated high levels of sensitivity (97.8%) and specificity (100%) compared with traditional visual interpretation by humans—experienced nurses and newly trained community health worker staff—and reduced the number of false positives and false negatives. Our findings lay the foundations for a new paradigm of deep learning–enabled diagnostics in low- and middle-income countries, termed REASSURED diagnostics¹, an acronym for real-time connectivity, ease of specimen collection, affordable, sensitive, specific, user-friendly, rapid, equipment-free and deliverable. Such diagnostics have the potential to provide a platform for workforce training, quality assurance, decision support and mobile connectivity to inform disease control strategies, strengthen healthcare system efficiency and improve patient outcomes and outbreak management in emerging infections.
... The LODs (limits of detection) reached 650 pg/mL and 190 pg/mL p24 antigen for spiked human serum and buffer, respectively. Allan-Blitz et al. 136 described a smartphone-based electronic reader to rapidly detect both HIV and syphilis at the POC. The antibodies specific to HIV were taken as the targets, and the sensitivity of this immunoassay can reach 98% concordance to the reference "gold standard" testing of 283 specimens. ...
To determine the diagnostic performance of the SD BIOLINE HIV/syphilis Duo rapid test.
A hospital-based cross-sectional study.
This evaluation was conducted at one of the largest hospitals in southern Ethiopia.
Serum samples obtained from clients attending the antiretroviral therapy and voluntary counselling and testing centres were used. Sera were originally collected for the purpose of investigating syphilis epidemiology. The performance of the test to detect HIV was evaluated using 400 sera (200 HIV positives and 200 HIV negatives). Also, its performance to detect syphilis was evaluated using 85 syphilis positive and 100 syphilis negative serum samples. Individuals <15 years of age or syphilis treated or those with ≤50 cells/µL CD4 cell count were originally excluded.
HIV screening was carried out according to the national rapid diagnostic testing (RDT) algorithm: Shenghai Kehua Bioengineering (KHB) test kit as a screening test, followed by the HIV1/2 STAT-PAK assay if positive. Where the result of the STAT-PAK is discordant with KHB, Unigold HIV is used as a tiebreaker to determine the result. We also used ELISA to resolve discordant HIV results. Syphilis serostatus was determined using the Treponema pallidum haemagglutination assay (TPHA).
The respective sensitivity, specificity, positive predictive value and negative predictive value of the SD BIOLINE HIV/syphilis Duo test were 100, 99.5, 99.5 and 100% for HIV and 97.6, 96, 95.4 and 98% for syphilis testing, respectively. In reference to TPHA, the test kit reported 4 false positives and 2 false negative results for syphilis. The κ values were 0.99 for HIV testing and 0.94 for syphilis testing.
The excellent performance of the SD BIOLINE HIV/syphilis Duo test to detect HIV as well as syphilis facilitates the integration of syphilis testing and treatment to the already established HIV prevention programme, ultimately contributing to the dual HIV and syphilis elimination goal.
Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
Routine antimicrobial susceptibility testing (AST) can prevent deaths due to bacteria and reduce the spread of multi-drug-resistance, but cannot be regularly performed in resource-limited-settings due to technological challenges, high-costs, and lack of trained professionals. We demonstrate an automated and cost-effective cellphone-based 96-well microtiter-plate (MTP) reader, capable of performing AST without the need for trained diagnosticians. Our system includes a 3D-printed smartphone attachment that holds and illuminates the MTP using a light-emitting-diode array. An inexpensive optical fiber-array enables the capture of the transmitted light of each well through the smartphone camera. A custom-designed application sends the captured image to a server to automatically determine well-turbidity, with results returned to the smartphone in ~1 minute. We tested this mobile-reader using MTPs prepared with 17 antibiotics targeting Gram-negative bacteria on clinical isolates of Klebsiella pneumoniae, containing highly-resistant antimicrobial profiles. Using 78 patient isolate test-plates, we demonstrated that our mobile-reader meets the FDA-defined AST criteria, with a well-turbidity detection accuracy of 98.21%, minimum-inhibitory-concentration accuracy of 95.12%, and a drug-susceptibility interpretation accuracy of 99.23%, with no very major errors. This mobile-reader could eliminate the need for trained diagnosticians to perform AST, reduce the cost-barrier for routine testing, and assist in spatio-temporal tracking of bacterial resistance.
Studies have addressed cost-effectiveness of syphilis testing of pregnant women in high-prevalence settings. This study compares costs of rapid syphilis testing (RST) with laboratory-based rapid plasma reagin (RPR) tests in low-prevalence settings in Peru. The RST was introduced in a tertiary-level maternity hospital and in the Ventanilla Network of primary health centers, where syphilis prevalence is approximately 1%. The costs per woman tested and treated with RST at the hospital were 369 respectively compared with 740 for RPR. For the Ventanilla Network the costs per woman tested and treated with RST were 295 respectively compared with 1454 for RPR. The cost per DALY averted using RST was 109 for RPR. RST showed lower costs compared to the WHO standard costs per DALY ($64). Findings suggest syphilis screening with RST is cost-effective in low-prevalence settings.
We assessed the laboratory performance of the Chembio Dual Path Platform® HIV-Syphilis rapid immunodiagnostic test and electronic reader for HIV and
Treponema pallidum
antibody detection in 450 previously characterized serum specimens. For HIV antibody detection, visual and electronic reader sensitivity was 100% and specificity was 98.7%. For
Treponema pallidum
antibody detection, test sensitivity was 94.7% and specificity was 100.0% for visual interpretation; the electronic reader's sensitivity was 94.7% and specificity was 99.7%.
Background
Quantifying sexually transmitted infection (STI) prevalence and incidence is important for planning interventions and advocating for resources. The World Health Organization (WHO) periodically estimates global and regional prevalence and incidence of four curable STIs: chlamydia, gonorrhoea, trichomoniasis and syphilis.
Methods and Findings
WHO’s 2012 estimates were based upon literature reviews of prevalence data from 2005 through 2012 among general populations for genitourinary infection with chlamydia, gonorrhoea, and trichomoniasis, and nationally reported data on syphilis seroprevalence among antenatal care attendees. Data were standardized for laboratory test type, geography, age, and high risk subpopulations, and combined using a Bayesian meta-analytic approach. Regional incidence estimates were generated from prevalence estimates by adjusting for average duration of infection. In 2012, among women aged 15–49 years, the estimated global prevalence of chlamydia was 4.2% (95% uncertainty interval (UI): 3.7–4.7%), gonorrhoea 0.8% (0.6–1.0%), trichomoniasis 5.0% (4.0–6.4%), and syphilis 0.5% (0.4–0.6%); among men, estimated chlamydia prevalence was 2.7% (2.0–3.6%), gonorrhoea 0.6% (0.4–0.9%), trichomoniasis 0.6% (0.4–0.8%), and syphilis 0.48% (0.3–0.7%). These figures correspond to an estimated 131 million new cases of chlamydia (100–166 million), 78 million of gonorrhoea (53–110 million), 143 million of trichomoniasis (98–202 million), and 6 million of syphilis (4–8 million). Prevalence and incidence estimates varied by region and sex.
Conclusions
Estimates of the global prevalence and incidence of chlamydia, gonorrhoea, trichomoniasis, and syphilis in adult women and men remain high, with nearly one million new infections with curable STI each day. The estimates highlight the urgent need for the public health community to ensure that well-recognized effective interventions for STI prevention, screening, diagnosis, and treatment are made more widely available. Improved estimation methods are needed to allow use of more varied data and generation of estimates at the national level.
Lateral flow assay tests are nowadays becoming powerful, low-cost diagnostic tools. Obtaining a result is usually subject to visual interpretation of colored areas on the test by a human operator, introducing subjectivity and the possibility of errors in the extraction of the results. While automated test readers providing a result-consistent solution are widely available, they usually lack portability. In this paper, we present a smartphone-based automated reader for drug-of-abuse lateral flow assay tests, consisting of an inexpensive light box and a smartphone device. Test images captured with the smartphone camera are processed in the device using computer vision and machine learning techniques to perform automatic extraction of the results. A deep validation of the system has been carried out showing the high accuracy of the system. The proposed approach, applicable to any line-based or color-based lateral flow test in the market, effectively reduces the manufacturing costs of the reader and makes it portable and massively available while providing accurate, reliable results.
To determine the laboratory-based performance and operational characteristics of three dual rapid diagnostic tests (RDTs) for testing HIV and syphilis.
Three dual RDTs (SD Bioline, Chembio, and MedMira) were evaluated using 1514 serum specimens archived at laboratories or collected from clinics in China and Nigeria to determine sensitivity and specificity, with 95% confidence intervals. Concordance of testing results read by two technicians, stability of testing results read at two time points, and test operation characteristics were also assessed.
All three of the evaluated RDTs gave excellent performance with a combined sensitivity ranging from 99.0%-99.6% for HIV and 98.3%-99.0% for syphilis, and a combined specificity ranging from 97.9%-99.0% for HIV and 97.2%-99.6% for syphilis. Concordance of testing results between two technicians and stability of testing results read within and one hour past the recommended reading period showed excellent agreement, with Kappa greater than or equal to 0.98.
All the tests were found to be very or fairly easy to use and easy to interpret the results. Further evaluations of these dual RDTs with whole blood in field settings, and more studies on the implication of introduction of these tests in HIV and syphilis control programs are needed.
Copyright © 2015. Published by Elsevier Ireland Ltd.
Purpose:
HIV rapid diagnostic tests (RDT) could be greatly contributive for a universal access to HIV diagnosis. However, according to the WHO, these tests need to be assessed before they can be used in routine.
Method and results:
We assessed 9 RDT in routine clinical use between 2009 and 2013. The sensitivity and specificity observed for 7 tests were≥99% and≥98%, respectively: FIRST RESPONSE HIV1-2-O PMC Medical, India, GENIE Fast HIV 1-2 and GENIE™ III HIV(1/2) Bio-Rad, France, HIV TRI-DOT+Ag;J. Mitra, INDIA; SD BIOLINE HIV(1/2) 3.0 and SD BIOLINE HIV/SYPHILIS DUO Standard Diagnostic, Korea; and VIKIA HIV(1/2); BioMérieux, France. Two tests had performances inferior to WHO recommendations: INSTI HIV1/2 Biolytical Canada; sensitivity=97.8% and HEXAGON HIV HUMAN GmbH Germany; specificity=94.8%.
Conclusion:
Seven of 9 RDT had excellent performances. Nevertheless, they can be used only after training staff, and taking into account national algorithm for their safe use.
Background
Point-of-care tests have the capacity to improve healthcare delivery by reducing costs and delay associated with care. A novel point-of-care immunochromatographic test for dual diagnosis of both HIV and syphilis by detecting IgG, IgM and IgA antibodies to HIV, and specific and recombinant Treponema pallidum antigens has recently been developed, but has not been evaluated in rural field settings. We evaluated the performance of the SD Bioline Syphilis/HIV Duo (Duo) assay at a healthcare center in rural Uganda.
Methods
A convenience sample of pregnant women attending Kinoni Health Centre IV from March to May, 2013 was enrolled. Venous blood was collected and centrifuged for plasma isolation. Samples were tested with the Duo assay and compared with the Treponema pallidum hemaglutination assay and paired HIV rapid antibody tests as the reference standards. The ease of use and time required for the Duo assay were also assessed by laboratory technicians.
Results
Two hundred twenty women were enrolled with a mean age of 25.00 years (SD 5.41). The sensitivity and specificity of the Duo assay were 100% (95% CI 79.0 – 100%) and 100% (95% CI 97.6 – 100.0) respectively, for syphilis, and, 100% (75.9 – 100%) and 99.5% (96.8 – 99.9%) respectively, for HIV. The duo kit was found to be faster and easier to use than the current HIV and syphilis testing techniques.
Conclusion
The sensitivity and specificity of the SD Bioline HIV/Syphilis Duo test were excellent in a field setting in Uganda. The Duo assay should be further evaluated in alternate populations and with point-of-care specimens (e.g. whole blood from finger stick specimens), but shows promise as a tool for improved HIV and syphilis surveillance, diagnosis, and treatment in field settings.
Massive implementation of malaria diagnostics in low-resource countries is regarded as a pivotal strategy in control and elimination efforts. Although malaria rapid diagnostic tests (RDTs) are considered a viable alternative, there are still obstacles to the widespread implementation of this strategy, such as reporting constraints and lack of proper quality assurance of RDT-based programmes at point-of-care (POC).
A prospective cohort of patients, seeking routine care for febrile episodes at health centres in malaria-endemic areas of Colombia, was used to assess the diagnostic performance of a device based on smartphone technology (Deki Reader TM, former codename "GenZero"), that assists users at POC to process RDTs. After informed consent, patients were enrolled into the study and blood samples were collected for thick blood smear (TBS) and RDT. The RDT results were interpreted by both visual inspection and Deki Reader device and concordance between visual and device interpretation was measured. Microscopy corrected by real-time polymerase chain reaction (PCR) and microscopy were "gold standard" tests to assess the diagnostic performance.
In total, 1,807 patients were enrolled at seven health centres in malaria-endemic areas of Colombia. Thirty-three Plasmodium falciparum and 100 Plasmodium vivax cases were positive by corrected microscopy. Both sensitivity and specificity were 93.9% (95% CI 69.7-95.2) and 98.7% (95% CI 98.5-99.4) for P. falciparum, and 98.0% (95% CI 90.3-98.9) and 97.9% (95% CI 97.1-98.5) for P. vivax. Percentage concordance between visual and device interpretation of RDT was 98.5% and 99.0% for P. vivax and P. falciparum, respectively.The RDT, when compared to TBS, showed high sensitivity and specificity for P. falciparum in both visual and device interpretation, and good overall diagnostic performance for P. vivax. Comparison between PCR as gold standard and visual and device interpretation showed acceptable overall performance for both species.
The diagnostic performance of the Deki Reader was comparable to visual interpretation of RDTs (without significant differences) for both malaria species. Providing standardized automated interpretation of RDTs at POC in remote areas, in addition to almost real-time reporting of cases and enabling quality control would greatly benefit large-scale implementation of RDT-based malaria diagnostic programmes.
The optimal treatment of early syphilis (primary, secondary and early latent) in HIV-infected patients remains controversial. The Center for Diseases Control STD Treatment Guidelines recommended 1 dose of benzathine penicillin G (BPG) regardless of HIV infection. However, many providers modify the treatment for early syphilis.
We performed a retrospective chart review of all cases of early syphilis with positive serologic test results in HIV-infected patients from May 2006 to May 2011 in 2 large, urban HIV clinics. Early syphilis includes primary, secondary, and early latent syphilis. Serological failure was defined as a lack of 4-fold decrease in rapid plasma reagent (RPR) titers 9 to 12 months after syphilis treatment. Patients whose RPR titers decreased after treatment and subsequently increased 4-fold at 9 to 12 months were excluded from the analysis of serological response because of possibility as "reinfection". Baseline characteristics were tested as predictive factors of serological failure using a univariate and multivariate logistic regression model, respectively.
Of 560 patients with confirmed cases of early syphilis, 51 (9.0%) experienced serological failure. Multivariate logistic regression modeling demonstrated that the predictive factors associated with serological failure after early syphilis treatment were baseline RPR titer <= 1:16 (OR 3.91[95%CI, 2.04- 7.47]), a previous history of syphilis (OR 3.12 [95%CI, 1.55- 6.26]), and a CD4 T-cell count below 350 cells/ml (OR 2.41 [95%CI, 1.27- 4.56]). Of note, type of syphilis treatment (1 dose versus 3 doses of BPG) did not appear to affect the proportion of serological failure (4% versus 10%, P = 0.29), however the power of this study to detect small differences was limited.
HIV-infected patients with baseline RPR titer <=1:16, syphilis history, and/or a CD4 T-cell count <350 cells/ml should be closely monitored for serologic failure after early syphilis treatment. This study did not detect a substantial difference between treatment with > 1 dose of BPG and decreased frequency of serological failure, supporting the current recommendation that one dose of BPG is adequate treatment for early syphilis in HIV-infected patients.
Further research is necessary to understand the factors contributing to the high prevalence of HIV/STIs among men who have sex with men (MSM) in Peru. We compared HIV/STI prevalence and risk factors between two non-probability samples of MSM, one passively enrolled from an STI clinic and the other actively enrolled from community venues surrounding the clinic in Lima, Peru.
A total of 560 self-identified MSM were enrolled between May-December, 2007. 438 subjects enrolled from a municipal STI clinic and 122 subjects enrolled during community outreach visits. All participants underwent screening for HIV, syphilis, HSV-2, gonorrhoea, and chlamydia and completed a survey assessing their history of HIV/STIs, prior HIV testing, and sexual behavior.
HIV prevalence was significantly higher among MSM enrolled from the clinic, with previously undiagnosed HIV identified in 9.1% compared with 2.6% of community participants. 15.4 % of all MSM screened were infected with ≥1 curable STI, 7.4% with early syphilis (RPR≥1∶16) and 5.5% with urethral gonorrhoea and/or chlamydia. No significant differences between populations were reported in prevalence of STIs, number of male sex partners, history of unprotected anal intercourse, or alcohol and/or drug use prior to sex. Exchange of sex for money or goods was reported by 33.5% of MSM enrolled from the clinic and 21.2% of MSM from the community (p = 0.01).
Our data demonstrate that the prevalence of HIV and STIs, including syphilis, gonorrhoea, and chlamydia are extremely high among MSM enrolled from both clinic and community venues in urban Peru. New strategies are needed to address differences in HIV/STI epidemiology between clinic- and community-enrolled samples of MSM.
Background
Parasitological confirmation of malaria is now recommended in all febrile patients by the World Health Organization (WHO) to reduce inappropriate use of anti-malarial drugs. Widespread implementation of rapid diagnostic tests (RDTs) is regarded as an effective strategy to achieve this goal. However, the quality of diagnosis provided by RDTs in remote rural dispensaries and health centres is not ideal. Feasible RDT quality control programmes in these settings are challenging. Collection of information regarding diagnostic events is also very deficient in low-resource countries.
Methods
A prospective cohort of consecutive patients aged more than one year from both genders, seeking routine care for febrile episodes at dispensaries located in the Bagamoyo district of Tanzania, were enrolled into the study after signing an informed consent form. Blood samples were taken for thick blood smear (TBS) microscopic examination and malaria RDT (SD Bioline Malaria Antigen Pf/Pan™ (SD RDT)). RDT results were interpreted by both visual interpretation and Deki Reader™ device. Results of visual interpretation were used for case management purposes. Microscopy was considered the “gold standard test” to assess the sensitivity and specificity of the Deki Reader interpretation and to compare it to visual interpretation.
Results
In total, 1,346 febrile subjects were included in the final analysis. The SD RDT, when used in conjunction with the Deki Reader and upon visual interpretation, had sensitivities of 95.3% (95% CI, 90.6-97.7) and 94.7% (95% CI, 89.8–97.3) respectively, and specificities of 94.6% (95% CI, 93.5–96.1) and 95.6% (95% CI, 94.2–96.6), respectively to gold standard. There was a high percentage of overall agreement between the two methods of interpretation.
Conclusion
The sensitivity and specificity of the Deki Reader in interpretation of SD RDTs were comparable to previous reports and showed high agreement to visual interpretation (>98%). The results of the study reflect the situation in real practice and show good performance characteristics of Deki Reader on interpreting malaria RDTs in the hands of local laboratory technicians. They also suggest that a system like this could provide great benefits to the health care system. Further studies to look at ease of use by community health workers, and cost benefit of the system are warranted.
Semi-quantitative thyroid stimulating hormone (TSH) lateral flow immunochromatographic assays (LFA) are used to screen for serum TSH concentration >5mIUL(-1) (hypothyroidism). The LFA format, however, is unable to measure TSH in the normal range or detect suppressed levels of TSH (<0.4mIUL(-1); hyperthyroidism). In fact, it does not provide quantitative TSH values at all. Obtaining quantitative TSH results, especially in the low concentration range, has until now required the use of centralized clinical laboratories which require specimen transport, specialized equipment and personnel, and result in increased cost and delays in the timely reporting of important clinical results. We have conducted a series of experiments to develop and validate an optical system and image analysis algorithm based upon a cell phone platform. It is able to provide point-of-care quantitative TSH results with a high level of sensitivity and reproducibility comparable to that of a clinical laboratory-based third-generation TSH immunoassay. Our research approach uses the methodology of the optimized Rayleigh/Mie scatter detection by taking into consideration the optical characteristics of a nitrocellulose membrane and gold nanoparticles on an LFA for quantifying TSH levels. Using a miniature spectrometer, LED light source, and optical fibers on a rotating benchtop apparatus, the light intensity from different angles of incident light and angles of detection to the LFA were measured. The optimum angles were found that the minimized Mie scattering from nitrocellulose membrane, consequently maximizes the Rayleigh scatter detection from the gold nanoparticles in the LFA bands. Using the results from the benchtop apparatus, a cell-phone-based apparatus was designed which utilized the embedded flash in the cell phone camera as the light source, piped the light with an optical fiber from the flash through a collimating lens to illuminate the LFA. Quantification of TSH was performed in an iOS application directly on the phone and verified using the code written in MATLAB. The limit of detection of the system was determined to be 0.31mIUL(-1) (never achieved before on an LFA format), below the commonly accepted minimum concentration of 0.4mIUL(-1) indicating clinical significance of hyperthyroidism. The system was further evaluated using human serum showing an accurate and reproducible platform for rapid and point-of-care quantification of TSH using a cell phone.
We demonstrate a cellphone-based rapid-diagnostic-test (RDT) reader platform that can work with various lateral flow immuno-chromatographic assays and similar tests to sense the presence of a target analyte in a sample. This compact and cost-effective digital RDT reader, weighing only ~65 g, mechanically attaches to the existing camera unit of a cellphone, where various types of RDTs can be inserted to be imaged in reflection or transmission modes under light-emitting diode (LED)-based illumination. Captured raw images of these tests are then digitally processed (within less than 0.2 s per image) through a smart application running on the cellphone for validation of the RDT, as well as for automated reading of its diagnostic result. The same smart application then transmits the resulting data, together with the RDT images and other related information (e.g., demographic data), to a central server, which presents the diagnostic results on a world map through geo-tagging. This dynamic spatio-temporal map of various RDT results can then be viewed and shared using internet browsers or through the same cellphone application. We tested this platform using malaria, tuberculosis (TB) and HIV RDTs by installing it on both Android-based smartphones and an iPhone. Providing real-time spatio-temporal statistics for the prevalence of various infectious diseases, this smart RDT reader platform running on cellphones might assist healthcare professionals and policymakers to track emerging epidemics worldwide and help epidemic preparedness.
Introduction of artemisinin combination therapy (ACT) has boosted interest in parasite-based malaria diagnosis, leading to increased use of rapid diagnostic tests (RDTs), particularly in rural settings where microscopy is limited. With donor support, national malaria control programmes are now procuring large quantities of RDTs. The scarcity of health facilities and trained personnel in many sub-Saharan African countries means that limiting RDT use to such facilities would exclude a significant proportion of febrile cases. RDT use by volunteer community health workers (CHWs) is one alternative, but most sub-Saharan African countries prohibit CHWs from handling blood, and little is known about CHW ability to use RDTs safely and effectively. This Zambia-based study was designed to determine: (i) whether Zambian CHWs could prepare and interpret RDTs accurately and safely using manufacturer's instructions alone; (ii) whether simple, mostly pictorial instructions (a "job aid") could raise performance to adequate levels; and (iii) whether a brief training programme would produce further improvement.
The job aid and training programme were based on formative research with 32 CHWs in Luangwa District. The study team then recruited three groups of CHWs in Chongwe and Chibombo districts. All had experience treating malaria based on clinical diagnosis, but only six had prior RDT experience. Trained observers used structured observation checklists to score each participant's preparation of three RDTs. Each also read 10 photographs showing different test results. The first group (n = 32) was guided only by manufacturer's instructions. The second (n = 21) used only the job aid. The last (n = 26) used the job aid after receiving a three-hour training.
Mean scores, adjusted for education, age, gender and experience, were 57% of 16 RDT steps correctly completed for group 1, 80% for group 2, and 92% for group 3. Mean percentage of test results interpreted correctly were 54% (group 1), 80% (group 2), and 93% (group 3). All differences were statistically significant (p < 0.05).
Manufacturer's instructions like those provided with the RDTs used in this study are insufficient to ensure safe and accurate use by CHWs. However, well-designed instructions plus training can ensure high performance. More study is underway to determine how well this performance holds up over time.
Rapid antibody tests for the detection of human immunodeficiency virus (HIV) offer an effective means of providing a timely result of HIV serostatus to individuals. The increased use of rapid HIV antibody tests outside the laboratory has highlighted the need for new, cost-effective quality assurance methods to be developed for use in nonlaboratory-based and resource-limited settings. Photographed rapid HIV test results were used in a modified external quality assessment scheme to assess the interpretation proficiency and, therefore, to assess the feasibility of using this method as a basis for a quality assessment program for nonlaboratory-based testing. Participants (n = 148), both experienced and inexperienced in the performance and interpretation of rapid HIV testing, interpreted the photographed results of five rapid HIV assays. These were scored according to the degree of technical discordance. Error scores were grouped according to each participant's technical experience. The accuracy of interpretation for four of the five assays was between 80 and 97%, indicating that the photographed results of samples, including those difficult to read or borderline difficult to read, can be used to assess the proficiency of test operators in interpreting results. Participants had greater difficulty in interpreting samples of weak reactivity; this was consistent across the five assays. Experience played an important role in accurate interpretation, with experienced laboratory participants exhibiting greater proficiency (P < 0.05) in interpreting the results of three of the five rapid HIV assays. It was established that photographed results of rapid HIV assays could be interpreted with accuracy and demonstrated that prior experience resulted in a more accurate interpretation performance.
Purpose of review:
Syphilis continues to cause morbidity and mortality worldwide. While syphilis infection is easily identifiable and treatable, rates of syphilis infection continue to increase among select populations in high-income countries and remain at endemic levels in low- and middle-income counties.
Recent findings:
World Health Organization recommended strategies have led to the dual elimination of mother-to-child transmission of syphilis and HIV in several countries, however outbreaks among select populations need to be adequately addressed.
Summary:
Continued vigilance and investment is needed to address syphilis worldwide. The epidemiology of syphilis differs in high-income and low- and middle-income counties.
Background:
Dual point-of-care tests for antibodies to human immunodeficiency virus (HIV) and Treponema pallidum allow for same-day testing and treatment and have been demonstrated to be cost-effective in preventing the adverse outcomes of HIV infection and syphilis. By recording and transmitting data as they are collected, electronic readers address challenges related to the decentralization of point-of-care testing.
Methods:
We evaluated a smartphone-based electronic reader using 201 sera tested with 2 dual rapid tests for detection of antibodies to HIV and T. pallidum in Los Angeles, USA, and Lima, Peru. Tests were read both visually and with the electronic reader. Enzyme immunoassay followed by Western blot and T. pallidum particle agglutination were the reference tests for HIV and T. pallidum, respectively.
Results:
The sensitivities of the 2 rapid tests for detection of HIV were 94.1% and 97.0% for electronic readings. Both tests had a specificity of 100% for detection of HIV by electronic reading. The sensitivities of the 2 rapid tests for detection of T. pallidum were 86.5% and 92.4% for electronic readings. The specificities for detection of T. pallidum were 99.1% and 99.0% by electronic reading. There were no significant differences between the accuracies of visual and electronic readings, and the performance did not differ between the 2 study sites.
Conclusions:
Our results show the electronic reader to be a promising option for increasing the use of point-of-care testing programs.
BACKGROUND:
Integrated prevention for HIV and syphilis is warranted because both syphilis and HIV infections have evidence-based, scalable interventions using current health care mechanisms. The advent of dual rapid point-of-care tests, single devices that can detect multiple infections using the same specimen, provides the opportunity to integrate the screening of syphilis into HIV prevention programs, potentially increasing the numbers of people tested and allowing for same-day testing and treatment. The aim of our study was to evaluate the MedMira Multiplo Rapid TP/HIV Antibody Test (MedMira Inc, Halifax, Nova Scotia, Canada), a qualitative, rapid immunoassay that detects antibodies to Treponema pallidum and HIV.
METHODS:
The reference test for comparison to the T. pallidum component of the Multiplo TP/HIV Test was the T. pallidum particle agglutination assay. For the HIV component, the reference test included a fourth-generation enzyme immunoassay with a confirmatory Western blot test.
RESULTS:
The sensitivity and specificity for the HIV antibody component were 93.8% (95% confidence interval [CI], 69.8%-99.8%) and 100% (95% CI, 97.7%-100%), respectively. The T. pallidum component of the test had a sensitivity of 81.0% (95% CI, 68.1%-94.6%) and a specificity of 100% (95% CI, 97.6%-100%).
CONCLUSIONS:
Our study showed excellent performance of the HIV antibody component of the test and very good performance for the T. pallidum antibody component of the MedMira Multiplo Rapid TP/HIV Antibody Test, which should be considered to improve screening coverage. Use of effective dual tests will create improved access to more comprehensive care by integrating the screening of syphilis into HIV prevention programs.
We demonstrate a compact and cost-effective imaging cytometry platform installed on a cell-phone for the measurement of the density of red and white blood cells as well as hemoglobin concentration in human blood samples. Fluorescent and bright-field images of blood samples are captured using separate optical attachments to the cell-phone and are rapidly processed through a custom-developed smart application running on the phone for counting of blood cells and determining hemoglobin density. We evaluated the performance of this cell-phone based blood analysis platform using anonymous human blood samples and achieved comparable results to a standard bench-top hematology analyser. Test results can either be stored on the cell-phone memory or be transmitted to a central server, providing remote diagnosis opportunities even in field settings.
In the Andean Region, HIV and sexually transmitted infections (STI) are most prevalent among men who have sex with men (MSM), but incidence estimates and associated factors have never been prospectively assessed.
A cohort of 1,056 high-risk HIV-negative MSM in Lima, Peru, were recruited during 1998-2000 (the ALASKA Cohort), and a nested case-control analysis was conducted between seroconverters and nonseroconverters, matched 1:3 by age and duration of follow-up for comparison of risk behaviors, acute retroviral symptoms, circumcision, and STI.
During average follow-up of 335 days, 34 men seroconverted, providing a HIV incidence estimate of 3.5 per 100 person-years [95% confidence interval (CI): 2.3 to 4.7]. High syphilis (8.4 per 100 person-years, 95% CI: 6.7 to 10.1) and herpes simplex virus type 2 (HSV-2) infection (10.4 per 100 person-years, 95% CI: 8.6 to 11.9) incidence estimates were obtained. HIV seroconverters were more likely than men who remained seronegative to report fever >or=3 days (46% vs. 7%), to seek medical care (62% vs. 27%), and to have >or=1 casual partner (86.2% vs. 74.1%) since their last visit. HIV seroconverters also were more likely to have acquired syphilis or HSV-2 infection (31% vs. 8% among initially HSV-2-seronegative men) although they were less likely to be circumcised (4.2% vs. 20.6%, a nonsignificant difference). In multivariate analysis, incident syphilis or HSV-2 infection (odds ratio [OR]: 5.9, 95% CI: 1.5 to 22.7) and sex with any casual partner (OR: 4.8, 95% CI: 0.9 to 26.2) were associated with HIV seroconversion.
STI that may cause anogenital ulcers are important risk factors for HIV acquisition among high-risk MSM in Lima, a population with a very high HIV incidence estimate. Synergistic interventions focusing in preventing both HIV and HSV-2, like male circumcision, are warranted to be assessed, especially in MSM populations with low levels of circumcision and high incidence estimates of ulcerative STI.
To determine prevalence of and risk factors associated with HIV and syphilis seropositivity and estimate incidence of HIV infection among Peruvian men who have sex with men (MSM) and characterize behaviors of men who report sex with both men and women ('bridgers').
Cross-sectional study of MSM in Lima, Peru.
Four-hundred and fifty-one MSM (of whom 442 responded to the question regarding sexual orientation) recruited through street outreach. Each was interviewed and underwent serologic testing for syphilis and HIV, including the less sensitive enzyme immunoassay test to estimate HIV incidence.
Overall, HIV and syphilis prevalence were 18.5% and 16.0%, respectively, with highest prevalence among cross-dressers (33.3% and 51.1%, respectively). The estimated overall HIV seroincidence was 11.2% per year (95% confidence interval, 4.8-23.6). Overall, 47.1% of men reported ever having sex with a woman: 78.6% of men self-identifying as heterosexuals, 85.1% of bisexuals, 35.5% of homosexuals, and 12.5% of cross-dressers. Of these, 26.5% were 'bridgers', of whom 55% reported two or more female partners during the last year. 'Bridgers' were less likely to have always used condoms during the past year for vaginal sex (17%) than for insertive anal sex with men (25.5%).
Among MSM in Peru, HIV and syphilis prevalence and HIV incidence were high, especially among cross-dressers. The high prevalence of bisexuality and low rates of consistent condom use, especially with female sexual partners indicates potential HIV transmission into the heterosexual population.
A mother in Haiti seeks prenatal care at a local health clinic accepts HIV voluntary counselling and testing and after testing HIV-positive takes short-course antiretroviral therapy for prevention of mother-to-child transmission (PMTCT). Postpartum she gives her baby antiretroviral therapy and provides artificial milk to protect against HIV transmission through breastfeeding. Is this a success story for PMTCT? No the baby died at 3 weeks from congenital syphilis. Is this an isolated case? No we have seen several babies in Haiti who have died of congenital syphilis after completion of PMTCT. The Haitian Government in collaboration with non-governmental organisations is leading the way in providing comprehensive care in its scale-up of HIV treatment programmes to include services for tuberculosis reproductive health and sexually transmitted diseases. (excerpt)