Cost and Impact of Dried Blood Spot Versus Plasma Separation Card for Scale-up of Viral Load Testing in Resource-limited Settings

• Published in: Clinical infectious diseases 2020-03, Vol.70 (6), p.1014-1020
• Main Authors: Nichols, Brooke E, Girdwood, Sarah J, Shibemba, Aaron, Sikota, Sharper, Gill, Christopher J, Mwananyanda, Lawrence, Noble, Lara, Stewart-Isherwood, Lynsey, Scott, Lesley, Carmona, Sergio, Rosen, Sydney, Stevens, Wendy
• Format: Article
• Language: English
• Subjects: and Commentaries; HIV Infections - diagnosis; HIV Infections - drug therapy; HIV-1 - genetics; Humans; Plasma; RNA, Viral; Sensitivity and Specificity; Specimen Handling; Viral Load; Zambia
• ISSN: 1058-4838; 1537-6591
• DOI: 10.1093/cid/ciz338

Abstract Background Routine plasma viral load (VL) testing is recommended for monitoring human immunodeficiency virus–infected patients on antiretroviral therapy. In Zambia, VL scale-up is limited due to logistical obstacles around plasma specimen collection, storage, and transport to centralized laboratories. Dried blood spots (DBSs) could circumvent many logistical challenges at the cost of increased misclassification. Recently, plasma separation cards (PSCs) have become available and, though more expensive, have lower total misclassification than DBSs. Methods Using a geospatial model created for optimizing VL utilization in Zambia, we estimated the short-term cost of uptake/correct VL result using either DBSs or PSCs to increase VL access on equipment available in-country. Five scenarios were modeled: (1) plasma only (status quo); (2) plasma at high-volume sites, DBS at low-volume sites; (3) plasma at high-volume sites, PSC at low-volume sites; (4) PSC only; (5) DBS only. Results Scenario 1 resulted in 795 342 correct results due to limited patient access. When allowing for full and partial adoption of dried specimens, access increases by 19%, with scenario 3 producing the greatest number of correct results expected (929 857). The average cost per correct VL result was lowest in the plasma + DBS scenario at $30.90 compared to $31.62 in our plasma + PSC scenario. The cost per correct result of using dried specimens only was dominated in the incremental analysis, due primarily to fewer correct results. Conclusions Adopting the partial use of dried specimens will help achieve improved VL access for patients at the lowest cost per correct result. Use of dried specimens can increase the number of patients accessing viral load (VL). Adopting partial use of dried specimens will help achieve improved VL access for patients at a lower cost per correct result than complete adoption of dried specimens.