Dilemmas in diagnosing advanced HIV disease: a case report of repeatedly false negative rapid HIV tests in a patient with epidemic Kaposi sarcoma in Tanzania

Despite global efforts to control Human Immunodeficiency Virus (HIV), a significant number of individuals present for care with advanced HIV disease. A false negative HIV test, where HIV-infected individuals receive negative test results, delays treatment initiation and increases transmission risks. We report a clinical case and outcome of a patient with advanced HIV infection who presented with repeated false negative rapid HIV tests. A 37-year-old Tanzanian woman presented at Muhimbili National Hospital (MNH) with respiratory symptoms, weight loss, and multiple purplish skin lesions suspicious of Kaposi sarcoma. Despite numerous negative rapid HIV test results at different healthcare and research facilities, she tested positive for HIV using Enzyme-Linked Immunosorbent Assay (ELISA) with a viral load of 747,000 copies/mL. A skin biopsy confirmed Kaposi sarcoma. She started on antiretroviral therapy (ART) however, she faced financial barriers to starting chemotherapy, her condition worsened, and she died. This case report shows that the HIV testing algorithm using rapid tests alone may lead to the misdiagnosis of critical HIV cases. It indicates a potential need for additional screening criteria for those testing negative. We recommend that global and national HIV guidelines incorporate pathways that account for false negative results in resource-limited countries to reduce advanced HIV disease incidence, mortality, and HIV transmission.