title: Prospective evaluation of diagnostic accuracy of dried blood spots from finger prick samples for determination of HIV-1 load with the NucliSENS Easy-Q HIV-1 version 2.0 assay in Malawi.
abstract: HIV-1 viral load (VL) testing is not widely available in resource-limited settings. The use of finger prick dried blood spot (FP-DBS) samples could remove barriers related to sample collection and transport. Measurement of VL using DBS from EDTA venous blood (VB-DBS) in place of plasma has previously been validated using the NucliSENS Easy-Q HIV-1 v2.0 assay, but information on the accuracy of FP-DBS samples for measuring VL is limited. This prospective study, conducted at Thyolo District Hospital in southern Malawi, compared VL levels measured on FP-DBS samples and plasma using the NucliSENS Easy-Q HIV-1 v2.0 assay. Comparability was assessed by means of agreement and correlation (131 patients with VLs of ≥100 copies/ml), sensitivity, and specificity (612 patients on antiretroviral treatment [ART]). Samples of EDTA venous blood and FP-DBS from 1,009 HIV-infected individuals were collected and prepared in the laboratory. Bland-Altman analysis found good agreement between plasma and FP-DBS VL levels, with a mean difference of -0.35 log10, and 95% limits of agreement from -1.26 to 0.55 log10. FP-DBS had a sensitivity of 88.7% (95% confidence interval [CI], 81.1 to 94.4%) and a specificity of 97.8% (95% CI, 96.1 to 98.9%) using a 1,000-copies/ml cut point and a sensitivity of 83.0% (95% CI, 73.4 to 90.1%) and a specificity of 100% (95% CI, 99.3 to 100%) using a 5,000-copies/ml cut point. This study shows that FP-DBS is an acceptable alternative to plasma for measuring VL using the NucliSENS Easy-Q HIV-1 v2.0. We are conducting a second study to assess the proficiency of health workers at preparing FP-DBS in primary health care clinics.
authors: Médecins Sans Frontières, Southern Africa Medical Unit, Cape Town, South Africa.
authors: Emmanuel
authors: E
authors: Fajardo
authors: Carol A
authors: CA
authors: Metcalf
authors: Pascale
authors: P
authors: Chaillet
authors: Lucia
authors: L
authors: Aleixo
authors: Pieter
authors: P
authors: Pannus
authors: Isabella
authors: I
authors: Panunzi
authors: Laura
authors: L
authors: Triviño
authors: Tom
authors: T
authors: Ellman
authors: Andrew
authors: A
authors: Likaka
authors: Reuben
authors: R
authors: Mwenda
mesh_terms: D000293:Adolescent; D000328:Adult; D001800:Blood Specimen Collection / Q000379:methods; D059788:Dried Blood Spot Testing / Q000379:methods*; D005260:Female; D015658:HIV Infections / Q000097:blood* / Q000175:diagnosis* / Q000821:virology; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D008295:Malawi; D008297:Male; D008875:Middle Aged; D010949:Plasma / Q000821:virology; D011446:Prospective Studies; D012367:RNA, Viral / Q000097:blood / Q000235:genetics; D019562:Viral Load / Q000235:genetics*; D055815:Young Adult
chemical_list: D012367:RNA, Viral