CD4 + lymphocyte counts are routinely ordered during the early phases of antiretroviral therapy and for prophylaxis of opportunistic infections in HIV-positive patients. Flow cytometry is the standard methodology for CD4 counts in Brazilian reference laboratories. However, these laboratories are located in large cities, frequently distant from patients, thus limiting patient access and delaying results. We compared a point-of-care test with flow cytometry determination of CD4(+) T lymphocyte counts in HIV patients. We analysed 107 consecutive samples by both methods. Overall, the point-of-care test performed well, with excellent agreement between it and the standard method. Test results were concordant for patients with CD4(+) T lymphocyte values above and below 200 cells/mm (3). The performance characteristics obtained were sensitivity 94% (95% CI 89.5-98.5%), specificity 93% (95% CI 88.2-97.8%), positive predictive value 86% (95% CI 79.4-92.6%), and negative predictive value 97% (95% CI 94-100%). The high sensitivity and specificity of the point-of-care test methodology suggest its utility as an alternative method for rapid measurement of CD4(+) T lymphocytes in patients with limited access to reference laboratories, enabling prompt therapeutic intervention for patients at risk of progression to AIDS.
Keywords: AIDS; Brazil; CD4 count; HIV; PIMA; flow cytometry; point-of-care test.
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