Background: An affordable and effective point-of-care test would increase access to testing for HIV-1 exposed infants and linkage to care for HIV-infected infants. The LYNX p24 antigen point-of-care test, developed by CIGHT at Northwestern University and Northwestern Global Health Foundation, was shown to be valid in laboratory and clinical studies and has the potential to reduce the time to diagnosis and treatment in rural sub-Saharan Africa.
Methods: From July 2014-June 2015, LYNX testing machines were evaluated at the Macha Hospital HIV clinic in rural Southern Province, Zambia. HIV-exposed infants requiring early infant diagnosis were enrolled. At the study visit, a dried blood spot card was collected for HIV DNA testing in Lusaka and a blood sample was collected for the LYNX test. The LYNX test was performed immediately by clinic counselors under observation by study staff. All steps in performing the LYNX test were assessed; HIV DNA test results were recorded.
Results: 156 infants (median age: 5.0 months; 48% male; 88% received PMTCT) were tested. 97% of tests were performed according to protocol. Among these, test results were available in a median of 55 minutes (IQR: 54, 58). Electricity was not available at the health care facility for 11% of tests (testing machines were operated using battery power). Eight infants tested positive and 137 tested negative by HIV DNA PCR (6 results yet to be returned). Of the 8 positive infants, 6 were also positive by the LYNX test (sensitivity: 75%; 95% CI: 35, 97). Of the 137 HIV DNA negative infants, 1 LYNX test was invalid and 136 were negative (specificity: 100%; 95% CI: 97, 100). The median time from sample collection to returning the HIV DNA PCR results to the mother was 90 days (IQR: 84, 141). Three mothers defaulted and 1 infant died while waiting for test results.
Conclusions: The LYNX test was successfully performed by counselors in rural health facilities and identified the majority of HIV-infected infants, without misdiagnosing any children. The LYNX test would significantly decrease the turnaround time for diagnosis in this setting, enabling HIV-infected infants to initiate antiretroviral therapy at an earlier age.

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