Laboratory Accuracy of Some Human Immunodeficiency Virus Screening Methods in a Nigerian Blood Bank: Is it time for Universal Adoption of Enzyme-linked Immuno-Sorbent Assay Methodologies as the Minimum Testing Paradigm?

Aim: To compare the prevalence rates, relevant indices of laboratory accuracy and proportion of false negative test results for some WHO recommended methodologies used for HIV screening amongst blood donor sata hospital-based blood bank in Nigeria.

Study Design: A cross-sectional.

Place and Duration: Blood bank unit of Jos University Teaching Hospital (JUTH) and the Nigerian National Blood Transfusion Service (NBTS) North Central Zonal Office, Jos between May and August 2008.

Methodology: Four hundred and forty blood donors (379 males and 61 females; aged 18-55 years) predominantly family replacement blood donors who met the minimum criteria to donate blood in Nigeria were included. Blood collection, serum processing, testing and interpretation of results were carried out using standard methods and manufacturers’ instruction. Serum was tested with a rapid test (Determine™ HIV- 1/2) and an EIA [Dia Pro HIV 1/2/0 ELISA] method. The samples were further tested with a 4th generation ELISA [GENSCREEN®PLUS HIV Ag- Ab ELISA].

Results: The prevalence of HIV in blood donors differed with the test method and assay as follows; Determine TM HIV 1/ 2 (3.6%), Dia Pro HIV 1/2/0 ELISA (5.5%) and GENSCREEN®PLUS HIV Ag-Ab ELISA (9.3) respectively.

Determine TM HIV-1/ 2gave a sensitivity of 0.39 (95% CI 0.24-0.55), specificity 1.00,95% CI 0.99-1.00), false negative [FN] (61%), positive predictive value [PPV] 1.00 95% CI 0.79-1.00), and a negative predictive value [NPV] 0.94, 95% CI 0.91-0.96 when compared with GENSCREEN®PLUS HIV Ag-Ab ELISA method. P<0.001.

Dia Pro HIV 1/2/0 ELISA gave a sensitivity of 0.54, 95% CI.37-0.69, specificity 0.995, 95% CI 0.99-1.00, FN(46.3%), PPV (0.9295% CI 0.73-0.99 and a NPV (0.95, 95% CI0.93-0.97) when compared with GENSCREEN®PLUS HIV Ag-Ab ELISA method. P<0.001.

Determine TM HIV 1/2 had a sensitivity of 0.67 95% CI 0.45-0.84, specificity of 1.00; 95% CI 0.99-1.00, FN (33.3%), PPV (1.00 95% CI 0.79-1.00 and a NPV 0.98, 95% CI 0.96-0.99 when compared with Dia Pro HIV 1/2/0 ELISA method. P<0.001.

Conclusion: The prevalence of HIV in blood donors is method dependent with GENSCREEN®PLUS HIV Ag-Ab ELISA higher than Dia Pro HIV 1/2/0 and Determine TM HIV 1/ 2. Dia Pro HIV 1/2/0 is more accurate and has fewer FN test results than Determine TM HIV 1/ 2. There is a need to discourage rapid testing as a major testing algorithm amongst hospital-based blood banks. Instead, ELISA methods should be adopted as the minimum testing paradigm. However, further testing with Nucleic Acid Amplification Testing (NAT) is recommended to validate reliability of this study.