Field performance of a thin-layer chromatography assay for detection of nevirapine in umbilical cord blood
Field performance of a thin-layer chromatography assay for detection of nevirapine in umbilical cord blood
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DOI：
10.1310/hct0705-263
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发表时间：
2006-09-01
影响因子：
--
通讯作者：
Stringer, Jeffrey S. A.
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文献类型：
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作者：
Chi, Benjamin H.;Lee, Alison;Stringer, Jeffrey S. A.
Purpose: Although cord blood surveillance can measure the effectiveness of nevirapine (NVP)-based programs for the prevention of mother-to-child HIV transmission (PMTCT), it requires the ability to detect nevirapine in plasma. At present, the only validated method is high-performance liquid chromatography (HPLC), a technique poorly suited for most resource-constrained settings. Method: We evaluated the field performance for a simple and inexpensive thin-layer chromatography (TLC) assay for NVP detection. We developed a conditional probability model to compare 2 testing algorithms: HPLC alone, and TLC screening followed by HPLC confirmation of negative results. Results: When compared to HPLC, sensitivity of TLC was 0.67 (95% confidence interval [CI] 0.49-0.84) and specificity was 0.84 (95% CI 0.69-0.95). In this sample-where overall NVP coverage was 49%-positive predictive value was 0.80 and negative predictive value was 0.72. At baseline with population NVP coverage of 33%, cost per specimen was lower in the TLC-HPLC testing algorithm ($40 vs. $50), and the proportion of false results was acceptable (11%). As population NVP coverage increased, cost-efficiency improved and error rate dropped substantially. Conclusion: TLC is reasonably sensitive and specific for NVP detection. A 2-step testing algorithm incorporating TLC and HPLC provides cost-efficiency at little expense to test performance.
