Use of the novel PanLeucogated CD4 test has saved over 600 million USD for South Africas HIV treatment programme: A 20-year retrospective costing analysis (2004 to 2024)

BackgroundIn 2004, South Africas public health system faced the dual challenge of rapidly scaling up antiretroviral therapy (ART) while reducing the cost of laboratory monitoring. At the time, conventional CD4 testing methods were expensive, labour-intensive, and impractical for sustaining a national testing network. This study aimed to assess the financial impact and cost savings associated with the implementation of the PanLeucogated CD4 (PLG/CD4) enumeration method between 2004 and 2024 in the public-sector in South Africa. MethodsA longitudinal cost analysis was conducted using annual test volumes and state tariffs for PLG/CD4 testing and the 4-colour CD3/CD4/CD8/CD45 T-cell enumeration reference method. Annual cost savings were calculated in United States Dollars (USD) by applying historical South African Rands (ZAR) to United States Dollars (USD) exchange rates. The state prices for tariff codes PLG/CD4 and the reference method were provided by calendar year in ZAR and converted to USD based on the prevailing exchange rate. The USD test prices were multiplied by annual test volumes. Cost savings were calculated by multiplying annual test volumes and the difference in test prices in USD (difference between PLG/CD4 and the reference method). ResultsThere were 50,745,848 PLG/CD4 tests performed over 20-years. The cost-per-test of PLG/CD4 was consistently lower than the reference method, ranging from $4,06 to $9,40, compared to $13,06 to $28,21. Cumulative national savings amounted to USD 626 million. The peak annual savings of $64,6 million occurred in 2011, coinciding with the height of ART enrolment. Cost savings persisted despite a doubling in the exchange rate over the study period. ConclusionThe PLG/CD4 implementation enabled cost-efficient, scalable, quality-assured CD4 testing as part of the national HIV response, reducing reliance on complex/costly technologies while improving coverage. These findings support the critical role of context-specific diagnostic innovation to strengthen health system resilience.