Until recently, many low- and middle-income countries were not able to provide HIV treatment to all patients due to the high cost of medication and treatment was reserved for only the sickest individuals. Decisions about whether or not to initiate patients on lifesaving antiretroviral therapy (ART) were often based on how far a patient’s disease had progressed.
HIV disease progression is typically measured by a patient’s CD4 count—a blood test that measures the concentration of CD4 T lymphocytes (white blood cells) in a sample. This test indicates how the immune system is functioning and it also helps providers determine a patient’s level of risk of acquiring an opportunistic infection or advancing to AIDS. Those who are identified as at risk of advanced HIV disease as a result of CD4 testing should then receive a package of services according to World Health Organization (WHO) guidelines. In some settings, CD4 testing is used to monitor a patient’s response to treatment.
Historically, CD4 testing was only accessible at central laboratories, even though the majority of patients access care at lower-level health care facilities. This discrepancy often led to delays in patients receiving their test results. As a result, some of the sickest patients could be delayed in starting lifesaving treatment until the CD4 test results were available.
The advent of point-of-care (POC) CD4 testing helped to curb these delays. POC CD4 testing allows tests to be conducted at health facilities while the patient waits. This technology, introduced over the last few years, has enabled patients to receive their test results within one visit and initiate treatment when appropriate.
In conjunction with the WHO, CHAI’s Laboratory Services Team (LST) and Applied Analytics Team (AAT) summarized and synthesized key findings from independent evaluations, pilots, and studies that have examined POC CD4 testing in an effort to better understand its effectiveness. Through careful review and analysis of published and unpublished evidence, this review found that POC CD4 technologies reduced the average time from HIV diagnosis to CD4 testing from 10.5 days to 0.1 days. The average time from HIV diagnosis to treatment initiation also decreased, from 31.5 days to 9.0 days. In addition, access to POC CD4 testing increased the percentage of patients receiving test results and initiating treatment compared to conventional laboratory-based CD4 testing.
Conclusions drawn from this analysis show that POC CD4 testing is useful for ensuring that patients receive their test results more quickly and that appropriate follow-up steps are taken. CHAI has also demonstrated similar impact for POC early infant diagnosis (EID), which is used to detect HIV infection in infants.
These findings helped to inform the WHO Consolidated Guidelines on the Use of Antiretroviral Drugs for Treating and Preventing HIV Infection. The guidelines state: CD4 cell count testing at the point of care can be used to prioritize patients for urgent linkage to care and ART initiation.
Research shows that the earlier patients begin treatment, the healthier they remain and less likely they are to spread the disease. Thanks to work by CHAI and other organizations, most countries have now expanded their HIV treatment eligibility criteria to ensure that all patients can initiate treatment immediately, regardless of CD4 count. This means that patients will be starting treatment earlier in the HIV disease progression process, which in turn will reduce risk of HIV-related complications and death and will help curb its spread. Regardless, CD4 will still be important in the future to prioritize patients for treatment in settings where treatment is not accessible to all, monitor patients on treatment where viral load testing is not available, and monitor and manage patients with advanced HIV disease and/or who are unstable on treatment.
