Fajardo E., Metcalf C.A., Chaillet P., Aleixo L., Pannus P., Panunzi I., Triviño L., Ellman T., Likaka A., Mwenda R.
Médecins Sans Frontières, Southern Africa Medical Unit, Cape Town, South Africa; Médecins Sans Frontières, Brussels, Belgium; Médecins Sans Frontières, Thyolo, Malawi; Ministry of Health, District Management Office, Thyolo, Malawi; Ministry of Health, Technical Support Services (Diagnostics), Lilongwe, Malawi
Fajardo, E., Médecins Sans Frontières, Southern Africa Medical Unit, Cape Town, South Africa; Metcalf, C.A., Médecins Sans Frontières, Southern Africa Medical Unit, Cape Town, South Africa; Chaillet, P., Médecins Sans Frontières, Brussels, Belgium; Aleixo, L., Médecins Sans Frontières, Thyolo, Malawi; Pannus, P., Médecins Sans Frontières, Thyolo, Malawi; Panunzi, I., Médecins Sans Frontières, Thyolo, Malawi; Triviño, L., Médecins Sans Frontières, Thyolo, Malawi; Ellman, T., Médecins Sans Frontières, Southern Africa Medical Unit, Cape Town, South Africa; Likaka, A., Ministry of Health, District Management Office, Thyolo, Malawi; Mwenda, R., Ministry of Health, Technical Support Services (Diagnostics), Lilongwe, Malawi
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. Copyright © 2014, American Society for Microbiology. All Rights Reserved.
antiretrovirus agent; virus RNA; adolescent; adult; aged; article; biochemical equipment; blood analysis; blood sampling; diagnostic accuracy; diagnostic test accuracy study; dried blood spot testing; female; human; Human immunodeficiency virus 1; Human immunodeficiency virus 1 infection; intermethod comparison; major clinical study; Malawi; male; nonhuman; nucleic acid amplification; prick test; priority journal; prospective study; sensitivity and specificity; validation process; viremia; virus identification; virus load; blood; dried blood spot testing; genetics; HIV Infections; Human immunodeficiency virus 1; middle aged; plasma; procedures; virology; young adult; Adolescent; Adult; Blood Specimen Collection; Dried Blood Spot Testing; Female; HIV Infections; HIV-1; Humans; Malawi; Male; Middle Aged; Plasma; Prospective Studies; RNA, Viral; Viral Load; Young Adult