Donna Gaffney’s research while affiliated with Parkland Memorial Hospital and other places

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Publications (6)


Syphilis Immunoassay Signal Strength Correlates with Active Infection in Pregnant Women
  • Article

January 2020

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21 Reads

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4 Citations

American Journal of Perinatology

Amanda C. Zofkie

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Angela R. Seasely

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Donna Gaffney

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[...]

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Emily H. Adhikari

Objective To evaluate the association of ARCHITECT chemiluminescent immunoassay (CIA) signal strength (signal-to-cutoff [S/CO] ratio), with maternal syphilis stage, rapid plasma reagin (RPR) reactivity, and congenital syphilis. Study Design A prospective observational study of reverse syphilis screening was conducted. Pregnant women were screened with CIA. Reactive CIA was reflexed to RPR; particle agglutination test (Treponema pallidum particle agglutination [TPPA]) was performed for CIA+/RPR− results. Clinical staging with history and physical was performed, and disease stage was determined. Prior treatment was confirmed. We compared S/CO ratio and neonatal outcomes among the following groups: Group 1: CIA+/RPR+/TPPA+ or CIA+/RPR−/TPPA+ with active syphilis; Group 2: CIA+/RPR−/TPPA+ or CIA+/serofast RPR/TPPA+, previously treated; Group 3: CIA+/RPR−/TPPA+, no history of treatment or active disease; Group 4: CIA+/RPR−/TPPA−, false-positive CIA. Results A total of 144 women delivered with reactive CIA: 38 (26%) in Group 1, 69 (48%) in Group 2, 20 (14%) in Group 3, and 17 (12%) in Group 4. Mean (±standard deviation) S/CO ratio was 18.3 ± 5.4, 12.1 ± 5.3, 9.1 ± 4.6, and 1.9 ± 0.8, respectively (p < 0.001). Neonates with overt congenital syphilis occurred exclusively in Group 1. Conclusion Women with active syphilis based on treatment history, clinical staging, and laboratory indices have higher CIA S/CO ratio and are more likely to deliver neonates with overt evidence of congenital syphilis.






Diagnostic accuracy of 4 th generation ARCHITECT HIV Ag/Ab Combo assay and utility of signal-to-cutoff ratio to predict false positive HIV tests in pregnancy

June 2018

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353 Reads

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27 Citations

American Journal of Obstetrics and Gynecology

Background: False positive HIV screening tests in pregnancy may lead to unnecessary interventions in labor. In 2014, the Centers for Disease Control and Prevention released a new algorithm for HIV diagnosis using a 4th generation screening test, which detects antibodies to HIV as well as p24 antigen and has a shorter window period compared with prior generations. A reactive screen requires a differentiation assay, and supplemental qualitative RNA testing is necessary for nonreactive differentiation assay. One screening test, the ARCHITECT Ag/Ab Combo assay, is described to have 100% sensitivity and >99% specificity in non-pregnant populations; however, its clinical performance in pregnancy has not been well described. Objective: To determine the performance of the ARCHITECT assay among pregnant women at a large county hospital and to assess if the relative signal-to-cutoff ratio can be used to differentiate between false positive versus confirmed HIV infections in women with nonreactive differentiation assay. Study design: This is a retrospective review of 4th generation HIV testing in pregnant women at Parkland Hospital between June 1, 2015 and January 31, 2017. We identified gravidas screened using the ARCHITECT Ag/Ab Combo assay (index test), with reflex to differentiation assay. Women with reactive ARCHITECT and nonreactive differentiation assay were evaluated with a qualitative RNA assay (reference standard). We calculated sensitivity, specificity, predictive value, and false positive rate of the ARCHITECT screening assay in our population, and described characteristics of women with false positive HIV testing versus confirmed infection. Among women with nonreactive differentiation assay, we compared interventions among women with and without qualitative RNA assay result available at delivery, and examined relative signal-to-cutoff ratios of the ARCHITECT assay in women with false positive versus confirmed HIV infection. Results: A total of 21,163 pregnant women were screened using the ARCHITECT assay, and 190 tested positive. Of these, 33/190 (17%) women had false positive HIV screening tests (28 deliveries available for analysis), and 157/190 (83%) had confirmed HIV-1 infection (140 available for analysis). Diagnostic accuracy of the ARCHITECT HIV Ag/Ab Combo assay in our prenatal population (with 95%CI) was as follows: sensitivity 100%(97.7%-100%), specificity 99.8%(99.8%-99.9%), positive likelihood ratio 636(453-895), negative likelihood ratio 0.0(NA), positive predictive value 83%(77%-88%), and false positive rate 0.16%(0.11%-0.22%), with prevalence 7/1,000. Women with false positive HIV testing were younger and more likely of Hispanic ethnicity. Qualitative RNA assay (reference standard) was performed prenatally in 24(86%) and quantitative viral load in 22(92%). Interventions occurred more frequently in women without qualitative RNA assay result available at delivery, including intrapartum zidovudine (75% vs 4%, p=0.002), breastfeeding delay (75% vs 8%, p=0.001) and neonatal zidovudine initiation (75% vs 4%, p=0.002). ARCHITECT signal-to-cutoff ratio was significantly lower for women with false positive HIV tests compared to those with established HIV infection (1.89 [1.27, 2.73] vs 533.65 [391.12, 737.22], respectively, p<0.001). Conclusion: While the performance of the 4th generation ARCHITECT HIV Ag/Ab Combo assay among pregnant women is comparable to that reported in non-pregnant populations, clinical implications of using a screening test with positive predictive value of 83% in pregnancy are significant. When qualitative RNA assay result is unavailable, absence of risk factors in combination with ARCHITECT HIV Ag/Ab assay S/Co ratio <5 and nonreactive differentiation assay provide sufficient evidence to support deferral of unnecessary intrapartum interventions while awaiting qualitative RNA results.

Citations (2)


... However, false-negatives can occur with TPPA because of the defects in coating and antigen selection, and the subjective judgment of results [5]. It has also been reported that a certain percentage of biological false positives can be detected with TPPA [5][6][7]. In this study, samples with inconsistent results of preliminary screening of anti-TP antibodies by ELISA and retest by TPPA were taken as experiment subjects for other WB tests. ...

Reference:

Confirmation value of Western blotting in detecting anti-treponema pallidum specific antibodies with suspicious results
Syphilis Immunoassay Signal Strength Correlates with Active Infection in Pregnant Women
  • Citing Article
  • January 2020

American Journal of Perinatology

... The missed detection of Architect ® could be explained by the less sensitivity to certain subtypes of HIV (Ly et al., 2012) or the influence on the assay due to viral mutation after treatment (Zuo et al., 2020). It has been reported that false-positive HIV Ag/Ab screening tests can be caused by other viral infections, autoimmune diseases, and multiple pregnancies (Mahajan et al., 2010;Liu et al., 2016;Adhikari et al., 2018). Our study indicated that no significant cross-reactivity or interference was observed from any of 15 potential interference factors assessed for the LiCA ® assay, including auto-antibodies, viral infections such as Epstein-Barr virus and hepatitis viruses, multiple pregnancies such as different stages of normal pregnancy and co-infection pregnancies, and various endogenous interferents. ...

Diagnostic accuracy of 4 th generation ARCHITECT HIV Ag/Ab Combo assay and utility of signal-to-cutoff ratio to predict false positive HIV tests in pregnancy
  • Citing Article
  • June 2018

American Journal of Obstetrics and Gynecology