The impact of a CD4 tiered service model on interlaboratory referral distances in South Africa

Abstract

Background: South Africa has the world’s largest human immunodeficiency virus (HIV) pandemic. Most service gaps for cluster of differentiation 4 (CD4) testing were previously addressed.
Aim: This study aimed to assess the impact of a tiered service on interlaboratory referral distances.
Setting: Data are reported for CD4 testing that are referred from a national network of laboratories.
Methods: Test volumes were extracted for source and testing laboratories from 2012 to 2021. The Euclidean distances (EDs) were calculated, with the annual and provincial medians reported and categorised (50 km, 51 km – 99 km, 100 km – 199 km, 200 km – 299 km and ≥ 300 km). The relationship between ED, referrals and turnaround time (TAT) was analysed. The change in the provincial median ED between 2012 and 2021 was calculated.
Results: Data included 14 487 006 referrals. The median ED ranged from 55 km to 60 km. An ED category of 51 km – 99 km, 100 km – 199 km, 200 km – 299 km and ≥ 300 km was reported for 35.1%, 13.2%, 3.5% and 0.3% of the specimens. A negative linear correlation was reported for ED with referral volumes (–0.1540) and TAT (–0.2305). The provincial median ED ranged from 16 km (Gauteng) to 186 km (Northern Cape). Excluding the Northern Cape, a provincial ED of ≤ 100 km was reported. The percentage change in median ED between 2012 and 2021 ranged from –55.7% (Free State) to 0.8% (Mpumalanga). Two source laboratories reported a median ED > 300 km in 2021 (Springbok and Beaufort West).
Conclusion: The study’s findings indicate that the decentralisation of services reduced the national median ED to below 60 km.
Contribution: The tiered implementation improved accessibility, however, some coverage gaps still remain.