Accuracy of a Dual Test for Detection of HIV1 and Syphilis at an Urban Hospital in Kampala- A cross-sectional study

Abstract

Background: Dual rapid point of care test kits for multiple infections such as HIV and syphilis can greatly improve the screening and detection of such infections in vulnerable groups. Methodology: A cross sectional study was conducted at St. Francis Hospital Nsambya ante natal clinic between 16th March and 3rd May 2015. All pregnant women attending the clinic for the first time were screened and eligible participants enrolled in the study after informed consent. Data was collected using structured questionnaire; whole blood was collected from participants by venapuncture. Data was entered into Epi data version 3.1 analysed with IBM SPSS version 16. Results: A total of 549 were screened for the study and 476 (86.7%) were tested for HIV and syphilis. Fifty two had already tested for HIV and syphilis and 21 left the clinic without being tested. Of those tested 9 had inconsistent data and 5 did not have confirmatory results due to mis- identification. Only 462 (84%) results were available for analysis. The sensitivity and specificity for ASTEL HIV and syphilis was 79% and 77% respectively. The PPV and NPV for ASTEL kit for HIV and Syphilis was 99%, 92 and 99, 93% respectively. The sensitivity /specificity/PPV and NPV for Determine HIV were 74%/100%/99% and 89% 38%/98%/96% and 92% for syphilis. The prevalence of HIV in the study was 4%, C.I 2-6% while that of syphilis was 6 %, C.I 4-8%. Conclusion: The sensitivity of the ASTEL kit for HIV and syphilis was lower than that given by the manufacturers and other laboratory based studies but was better than that of the routine Determine tests. The low prevalence of HIV and syphilis in this study population may have resulted in a higher proportion of false negatives hence affecting the positive and negative predictive values