Analytical and Clinical Performance Evaluation of the Elecsys HIV combi PT Assay on the cobas e 602 Analyzer for the Diagnosis of Human Immunodeficiency Virus.

OBJECTIVES: We evaluated the performance of the Elecsys HIV combi PT assay on the cobas e 602 analyzer for diagnosing human immunodeficiency virus (HIV; part of the US Food and Drug Administration [FDA] submission). METHODS: The HIV combi PT and reference (ARCHITECT HIV Ag/Ab Combo) assays were assessed at four independent clinical laboratories/one reference laboratory (United States; July 2014 to November 2015). Clinical performance was evaluated using four reagent lots. Analytical performance was evaluated per Clinical and Laboratory Standards Institute EP05-A3 guidelines. Serum/plasma samples from 18 clinical sites/vendors (United States and outside the United States) were tested. RESULTS: Sensitivity (95% confidence interval [CI]) in HIV-1 antibody-positive individuals (United States and outside the United States; n = 1,460) was 100.00% (99.75%-100.00%). Specificity was 99.94% (95% CI, 99.85%-99.98%) in low-risk individuals (United States; n = 6,843), 98.19% (95% CI, 96.93%-99.04%) in high-risk individuals (United States and outside the United States; n = 758), and 97.43% (95% CI, 95.32%-98.76%) in pregnant women (United States and outside the United States; n = 440). Analytical performance was acceptable. CONCLUSIONS: We demonstrate the robustness of the FDA-approved Elecsys HIV combi PT assay on the cobas e 602 analyzer for HIV testing in the United States.

Evaluation of the Elecsys Syphilis Immunoassay for Detection of Syphilis in Populations at Risk of Disease in the US and Argentina.

BACKGROUND: The Elecsys® syphilis immunoassay is an automated, qualitative immunoassay that uses a double-antigen sandwich format to detect antibodies to Treponema pallidum in human serum and plasma. We aimed to validate performance of the immunoassay in various populations at risk for syphilis infection in the US and Argentina. METHODS: Samples were obtained for a number of study cohorts, including participants from routine syphilis testing at high or low risk for syphilis, HIV-positive patients, pregnant women, and patients in various stages of syphilis infection. The primary objective was to validate the Elecsys syphilis immunoassay by comparing it with a composite testing algorithm using US Food and Drug Administration (FDA)-approved tests, including the predicate IMMULITE 2000 syphilis screening assay, the rapid plasma reagin, and the T. pallidum particle agglutination assay. RESULTS: Complete algorithm testing was performed on all 2660 collected samples. Acceptable precision was demonstrated in all samples. Comparison of the Elecsys syphilis immunoassay with the final syphilis status for all samples yielded a diagnostic sensitivity of 99.5% (95% CI, 98.21-99.94) and a diagnostic specificity of 99.2% (95% CI, 98.69-99.49). Overall, the lower limit of the 95% CIs for sensitivity and specificity met the expected performance of ≥95%. CONCLUSION: This is the first study that confirms the high sensitivity and specificity of the Elecsys syphilis immunoassay in US and Argentinian cohorts and highlights the assay's usefulness as an alternative to current tests for the diagnosis of syphilis infection in a broad range of participant cohorts.

Rates of vaso-vagal reactions among first time teenaged whole blood, double red cell, and plateletpheresis donors.

Given the paucity of published data regarding reaction rates in younger teenaged donors, we evaluated the reaction rates in all of our first time teenaged donors after New York Blood Center lowered the minimum permissible age for blood donations from 17 to 16 yr in 2005. The overall rates of vaso-vagal reactions in donors aged 16 to 19, and those resulting in syncope, occurring in 72,769 consecutive first time whole blood, 3,822 double red cell, and 777 platelet apheresis donations were calculated. They were correlated with age and compared to those found in donors aged 20-29. Separate rates were calculated by gender, age in yr, and donation type, and then compared to each other. The overall reaction rate among first time teenaged whole blood donors was 8.2% and was significantly greater than among plateletpheresis donors (4.0%; p <0.0002). The rate in female whole blood donors (10.0%) was significantly higher than in males (6.4%; p <0.0002). In male double red cell donors the overall reaction rate of 3.5% was significantly lower than that found in male whole blood donors (p <0.002). Among both male and female whole blood donors a significant correlation with decreasing donor age between 19 and 16 yr was found (r(2) = 0.981; p = 0.01) and (r(2) = 0.988; p = 0.006), respectively. We conclude that teenaged donors have increased reaction rates when compared to adults and the reaction rates increase with decreasing age. In addition, females have higher reaction rates than males. Finally, reaction rates associated with apheresis donations are significantly lower than those associated with whole blood donations.