Abstract
BackgroundSince 2010, point-of-care (POC) CD4 testing platforms have been introduced in both urban and rural settings to expand access to testing by bringing diagnostic services closer to patients. We conducted an analysis of routinely collected CD4 testing data to determine the invalid result rates associated with POC CD4 testing.MethodsWe analyzed 981,152 CD4 testing records collected from Alere Pima Analyzers between January 2011 and December 2016 across five countries in sub-Saharan Africa. Routinely collected data and programmatic records were used to determine the rate of invalid test results per month, by facility type, and by operator based on cumulative usage during the study period. In addition, frequency of invalid test types and utilization of control beads were assessed.ResultsAcross the five countries, 75,530 invalid messages were returned, resulting in an overall invalid result rate of 7.7%. The invalid result rate by country ranged from 6.6% to 11.2%. Invalid result rates were consistent across facility types. Invalid result rates were inversely correlated with operator usage: low volume operators (<50 tests over study period) experienced an invalid result rate of 10.2%, while high volume operators (>500 tests over study period) experienced an invalid result rate of 5.5%. Two invalid result types (exposure position control and reagent control) accounted for nearly 50% of invalid results. Routine data showed that control beads were run on 88.3% of days that the device was used.ConclusionsOur analysis found that the rate of invalid results was consistent across all types of health facilities, indicating that decentralization of POC CD4 testing to lower level health facilities did not exhibit high invalid result rates or increase cartridge wastage. Additionally, invalid result rates were inversely correlated to operator usage, with high-volume operators experiencing lower invalid result rates than low-volume operators. POC CD4 testing can, therefore, be performed in decentralized national testing programs; however, adequate training, quality assurance, routine monitoring, and ongoing mentorship should also be implemented for success.
Highlights
CD4 enumeration has previously been used in resource-limited settings to determine treatment eligibility of HIV-positive patients and for routine monitoring to identify treatment failure and opportunistic infections [1,2]
Our analysis found that the rate of invalid results was consistent across all types of health facilities, indicating that decentralization of POC CD4 testing to lower level health facilities did not exhibit high invalid result rates or increase cartridge wastage
Invalid result rates were inversely correlated to operator usage, with high-volume operators experiencing lower invalid result rates than low-volume operators
Summary
CD4 enumeration has previously been used in resource-limited settings to determine treatment eligibility of HIV-positive patients and for routine monitoring to identify treatment failure and opportunistic infections [1,2]. The WHO has recently re-affirmed the continued importance of CD4 testing for clinical patient and opportunistic infection management, identification of patients with advanced HIV disease, and in areas with limited access to viral load testing [4,5]. Considerable investments made in CD4 testing networks have resulted in sufficient testing capacity to provide CD4 access to all people living with HIV [6]. Despite the available testing capacity, access to CD4 testing is still poor for many people living with HIV. We conducted an analysis of routinely collected CD4 testing data to determine the invalid result rates associated with POC CD4 testing
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