False-positive rapid diagnostic tests in paediatric and obstetric patients in South Africa

Providing easily accessible, quick and accurate human immunodeficiency virus (HIV) testing services (HTS) is central to achieving the Joint United Nations Programme on HIV/AIDS (UNAIDS) 90-90-90 targets. Rapid diagnostic tests (RDTs) for HIV are affordable and technically easy to perform. Two positive RDTs from different manufacturers are required to make a diagnosis of HIV in South Africa. Difficulty arises when there are discordant results from the two kits. In this case report, we will discuss four instances of false-positive RDTs.

Case 1 is a 10-year-old female, referred for initiation of antiretroviral treatment (ART). She was diagnosed using two of the same brand RDT at her local clinic. Case 2 is a 21-year-old female who presented to obstetric admissions in labour. Case 3 is a 39-year-old female who was screened for HIV during a routine antenatal appointment. Case 4 is a 22-year-old female who was admitted 21 days postpartum with puerperal sepsis. All four cases had discordant RDTs when screened for HIV at our facility.

The results of all the investigations conducted on all four patients confirmed HIV negative status. The reference laboratory verified the results and reran the RDTs, which remained discordant. This confirmed a false-positive result in all four cases with the screening RDT.

With high numbers tested and a low yield of new cases, each individual case of discordancy may cause unnecessary distress, confusion and treatment, particularly in high-risk scenarios like pregnancy. Trends of false-positive and discordant RDT results should be monitored and inform HTS guidelines.