Point-of-care testing for cryptococcal disease among hospitalized human immunodeficiency virus-infected adults in Ethiopia

Abstract

In a cross-sectional study among hospitalized human immunodeficiency virus (HIV)-infected patients in Ethiopia, we sought to determine the rates and predictors of cryptococcal disease and evaluate the test performance of a recently introduced point-of-care test for Cryptococcus neoformans detection in various biological samples. We tested serum, urine, and fingerstick blood samples from each patient with a cryptococcal antigen lateral flow assay (CRAG LFA; Immuno Mycologic Inc., Norman, OK). Cerebrospinal fluid was collected at the discretion of the treating physician. Logistic regression was used to identify risk factors for a positive test result. Agreement between different sample types was also assessed. Among 198 hospitalized HIV-infected patients with a median CD4 count of 93 cells/mm3, 18 patients (9.1%) had a positive serum CRAG LFA. Of these, 16 (8.1%) had confirmed cryptococcal meningitis (CM), all of whom had a positive fingerstick blood LFA result. There was a very high agreement between CRAG LFA tests in serum and fingerstick blood samples (κ = 0.97, 95% confidence interval [CI] = 0.91-1.00); this was higher than that between serum and urine samples (κ = 0.76, 95% CI = 0.58-0.93). A CD4 count < 100 cells/mm3 was significantly associated with a positive CRAG LFA. The absence of fever, headache, meningismus, and neck stiffness had a negative predictive value of 100% for CM. In addition to finding high rates of cryptococcal disease, our study demonstrated that the use of the LFA on fingerstick whole blood is less invasive, and an effective method for CM case finding among hospitalized patients with HIV.