BACKGROUND: The 2-tier serologic testing protocol for Lyme disease has a number of shortcomings including low sensitivity in early disease; increased cost, time, and labor; and subjectivity in the interpretation of immunoblots. METHODS: The diagnostic accuracy of a single-tier commercial C6 ELISA kit was compared with 2-tier testing. RESULTS: The C6 ELISA was significantly more sensitive than 2-tier testing with sensitivities of 66.5% (95% confidence interval [CI] 61.7-71.1) and 35.2% (95% CI 30.6-40.1), respectively (P < 0.001) in 403 sera from patients with erythema migrans. The C6 ELISA had sensitivity statistically comparable to 2-tier testing in sera from Lyme disease patients with early neurologic manifestations (88.6% versus 77.3%, P = 0.13) or arthritis (98.3% versus 95.6%, P = 0.38). The specificities of C6 ELISA and 2-tier testing in over 2200 blood donors, patients with other conditions, and Lyme disease vaccine recipients were found to be 98.9% and 99.5%, respectively (P < 0.05, 95% CI surrounding the 0.6 percentage point difference of 0.04 to 1.15). CONCLUSIONS: Using a reference standard of 2-tier testing, the C6 ELISA as a single-step serodiagnostic test provided increased sensitivity in early Lyme disease with comparable sensitivity in later manifestations of Lyme disease. The C6 ELISA had slightly decreased specificity. Future studies should evaluate the performance of the C6 ELISA compared with 2-tier testing in routine clinical practice.
[Show abstract][Hide abstract] ABSTRACT: Current serodiagnostic assays for Lyme disease are inadequate at detecting early infection due to poor sensitivity and non-specificity that arise from the use of whole bacteria or bacterial proteins as assay targets; both targets contain epitopes that are cross-reactive with epitopes found in antigens of other bacteria species. Tests utilizing peptides that containing individual epitopes highly-specific for Borrelia burgdorferi as diagnostic targets are an attractive alternative to current assays. Using an overlapping peptide library, we mapped linear epitopes in OspC, a critical virulence factor of B. burgdorferi required for mammalian infection, and confirmed the results by ELISA. We identified a highly conserved 20-amino acid peptide epitope, OspC1. Via ELISA, OspC1 detected specific IgM and/or IgG in 60 out of 98 serum samples (62.1%) obtained from patients with erythema migrans (early Lyme disease) at the time of their initial presentation. By comparison, the commercially available OspC peptide, PepC10, detected antibody in only 48 of 98 serum samples (49.0%). In addition, OspC1 generated fewer false positive results among negative healthy and disease (rheumatoid arthritis and RPR+) control populations compared to PepC10. Both highly specific and more sensitive than currently available OspC peptides, OspC1 could have value as a component of a multi-peptide Lyme disease serological assay with significantly improved capabilities for the diagnosis of early infection.
[Show abstract][Hide abstract] ABSTRACT: In recent years, there has been rapidly growing interest in developing hand held, sensitive and cost-effective on-chip biosensing systems that directly translate the presence of certain bioanalytes (e.g., biomolecules, cells and viruses) into an electronic signal. The impressive and rapid progress in micro- and nanotechnology as well as in biotechnology enables the integration of a variety of analytical functions in a single chip. All necessary sample handling and analysis steps are then performed within the chip. Microfluidic systems for biomedical analysis usually consist of a set of units, which guarantees the manipulation, detection and recognition of bioanalytes in a reliable and flexible manner. Additionally, the use of magnetic fields for performing the aforementioned tasks has been steadily gaining interest. This is because magnetic fields can be well tuned and applied either externally or from a directly integrated solution in the biosensing system. In combination with these applied magnetic fields, magnetic nanoparticles are utilized. Some of the merits of magnetic nanoparticles are the possibility of manipulating them inside microfluidic channels by utilizing high gradient magnetic fields, their detection by integrated magnetic microsensors, and their flexibility due to functionalization by means of surface modification and specific binding. Their multi-functionality is what makes them ideal candidates as the active component in miniaturized on-chip biosensing systems. In this review, focus will be given to the type of biosening systems that use microfluidics in combination with magnetoresistive sensors and detect the presence of bioanalyte tagged with magnetic nanoparticles.
International Journal of Molecular Sciences 09/2013; 14(9):18535-56. DOI:10.3390/ijms140918535 · 2.86 Impact Factor
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