Accuracy Evaluation of HIV Rapid Tests Resolved by Tie-Breaker: a Case Study of Nigerian Serial Algorithm

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Authors : Suleiman Mohammed Aminu



The World Health Organization strongly recommended test algorithm for diagnosis of Human Immunodeficiency Virus (HIV) infection. In either parallel or serial algorithms, discordance is commonly encountered and the final result has to be determined by the use of a tie breaker.


The objective of this study is to evaluate the accuracy of HIV rapid test results resolved by tie breaker in a serial algorithm using Western Blot as gold standard.


A total of 110 remnant samples reactive as positive by Determine but giving discordant result with Unigold were collected and retested by national (serial) algorithm from January 2013 to July 2013. Samples were collected in either plain bottles or EDTA container by staff conducting HIV rapid test and transported/stored at 2-8 degree Celsius. Samples were tested according to manufactures leaflet insert. The final result obtained with the serial algorithm was verified with Western Blot technique.


Out of the 10 discordant results, 9 were confirmed HIV positive by serial algorithm but only 8 were confirmed positive by Western Blot technique. Thus, there was 1(11%) false positive obtained with serial algorithm. Samples that were reactive by Determine were 110 (100%), 94(85.5%) reactive for Unigold and 93(85%) reactive results with Stat Pak.


One out of every 9 HIV results resolved by tie breaker as positive is false positive. This accounts for 11%. There is need therefore to introduce further means of verifying positive results resolved by tie breaker to avoid placing patients on anti retro vial drugs wrongly and subjecting people to psychological trauma.


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