Development and validation of a simple and rapid way to generate low volume of plasma to be used in point-of-care HIV virus load technologies

Abstract

A new point-of-care HIV viral load, mPIMA HIV-1/2 VL, Abbott, USA, has been recently developed. This point-of-care viral load requires no skilled person to run and uses a small plasma volume (50μL). However, obtaining 50μL of plasma can be a challenge in limited resource settings. We validated a simple and easy method to obtain enough amount of plasma to run a point-of-care viral load. The study utilized 149 specimens from patients failing antiretroviral therapy. At least 250μL of whole blood was collected in a microtube/EDTA from fingerstick (fs-plasma) and immediately centrifuged. Parallel collection of venous blood to obtain plasma (vp-plasma) was used to compare performance in a point-of-care viral load assay and in methodology used in centralized laboratories Abbott M2000, Abbott, USA. The procedure for plasma collection takes less than 10min and in 94% of the cases only one fingerstick was sufficient to collect at least 250μL of blood. The Pearson correlation coefficient value for vp-plasma versus fs-plasma ran on mPIMA was 0.990. The Bland-Altman mean difference (md) for this comparison were virtually zero (md=-0.001) with limits of agreement between -0.225 and 0.223. In addition, the Pearson correlation coefficient value for fs-plasma in mPIMA versus vp-plasma in Abbott M2000 was 0.948 for values above the mPIMA limit of quantification (LoQ; from 800 to 1,000,000copies/mL). These results validate this simple plasma isolation method capable to be implemented in low resource countries where point-of-care decentralization is deeply needed.

Keywords: Fingerstick-plasma; HIV; HIV viral load; POC VL; Point-of-care; mPIMA.

Copyright © 2019 Sociedade Brasileira de Infectologia. Published by Elsevier España, S.L.U. All rights reserved.

Figures

Fig. 1

Alternative procedure to generate plasma in sites with no laboratory infrastructure. Each frame represents: 1, fingerstick; 2, collecting the blood flow; 3, blood collected in microtube; 4, minifuge assemble with UPS; 5, collecting plasma with a 50 μL fixed volume pippet; 6, loading mPIMA cartridge; 7, inserting the cartridge in mPIMA; 8, result displayed in mPIMA; 9, printing result; 10, full mPIMA apparatus set up.

Fig. 2

(A) and (C) show the linear regression and (B) and (D) Bland–Altman analysis, respectively, from VL results using and vp-plasma assayed by Abbott m2000 versus vp-plasma and fs-plasma assayed by mPIMA (n = 149 plasma specimens). In (A) and (C), a continuous line shows the LR line. (B) and (D) show the average VL obtained by Abbott vp-plasma minus mPIMA vp-plasma (B) or minus mPIMA fs-plasma (D) versus the VL difference between specimens: dashed line indicates de mean difference between VL of two specimens and dotted lines the limits of agreement of the mean difference. All data shown were log10 transformed.

Fig. 3

(A) and (B) show the linear regression and Bland–Altman analysis, respectively, from VL results using and VP and FS plasma collection methodologies, generated on the mPIMA technology (n = 149 plasma specimens). In (A), a continuous line shows the LR analysis and dashed line indicates the equality line. (B) shows the average VL obtained by VP and FS versus the difference between specimens obtained by VP and FS: dashed line indicates de difference (VP-FS) and dotted lines the limits of agreement. All data shown were log10 transformed.