Performance Characteristics of Urine HIV Screening Methods against Blood-Based Methods for Surgeons Guide

Abstract

Testing for Human Immunodeficiency Virus (HIV), widely distributed in sub-Saharan Africa since it is mainly invasive but, could be non-invasive and quick also, reducing waiting time especially when required for presurgical procedures. This study determined the HIV status of patients using Urine screening test method and to compare its performance to blood-based testing methods. The routine pre and post-test counselling for HIV screening were done for all provider-initiated HIV testing using blood-based screening methods. Due to the cost and unavailability of enough urine testing kits, only patients who tested positive for HIV with blood-based methods and were scheduled for surgery or a surgical procedure were enrolled in the study. Informed consent was obtained. Paired urine and blood samples were collected at the same visit into clean universal bottles and analyzed immediately. A colloidal gold enhanced rapid immuno-chromatographic assay (Alliance Biomedical) kit for the rapid qualitative detection of antibodies to Human Immunodeficiency Virus (HIV) I and II in urine were used in comparison to the standard HIV testing of ante-cubital venous blood collected in EDTA vacutainer and analyzed using Determine (T) HIV 1 and 2 in vitro qualitative immunoassay strip, UNI GOLD rapid test kit and the Chembio HIV 1/2 STAT PAK assay strip. A total of 7568 patients were tested for routine provider-initiated HIV testing, 521 tested HIV positive. There were 105 (20.15%) males and 416 (79.85%) females, age ranged from 15 years to >80 years. Most of the surgeries performed were Caesarian section 93 (37%), Hernia 55 (22%), Lumps 48 (19%), Acute appendicitis 33 (13%), Uterine fibroids 10 (4%), Ruptured ectopic pregnancy 2 (1%) and others (Intestinal obstruction, Postoperative adhesions, Ingrown toe nails, Breast abscess, Hemorrhoids, Anal fissures etc.) 10 (4%). DETERMINE RAPID HIV TEST METHOD USING BLOOD: A total of 521 HIV positive samples were tested, 502 (96.35%) tested HIV positive and 19 (3.65%) tested HIV negative. These 19 HIV negatives were re-tested with Stak Pak: 19 (100%) tested HIV positive. UNI GOLD HIV TEST METHOD USING BLOOD: A total of 521 HIV positive samples were tested, 521 (100%) tested HIV positive. URINE TESTING METHOD: A total of 251 (48.18%) of the 521 HIV positive patients were scheduled to undergo a surgical procedure. These were re-tested using the Urine testing method, 235 (93.63%) tested HIV positive while 16 (6.37%) tested negative. The blood sample of the 16 who tested negative using the Urine testing method was subjected to confirmatory test using Stat Pak and all 16 (100%) tested HIV positive. The specificity for Unigold and Determine blood testing was 100%. All three tests had a Positive Predictive Value (PPV) of 100% while the Negative Predictive Values (NPV) were 100% and 99.73% for Unigold and Determine respectively. The use of Urine HIV testing method compared well to the blood HIV testing methods and could be a better non-invasive sample method for screening of HIV/AIDS in the population especially among surgeons’ pre-surgical procedures.