Evaluation of Two Techniques for Viral Load Monitoring Using Dried Blood Spot in Routine Practice in Vietnam (French National Agency for AIDS and Hepatitis Research 12338)

Abstract

Background. Although it is the best method to detect early therapeutic failure, viral load (VL) monitoring is still not widely available in many resource-limited settings because of difficulties in specimen transfer, personnel shortage, and insufficient laboratory infrastructures. Dried blood spot (DBS) use, which was introduced in the latest World Health Organization recommendations, can overcome these difficulties. This evaluation aimed at validating VL measurement in DBS, in a laboratory without previous DBS experience and in routine testing conditions.Methods. Human immunodeficiency virus (HIV)-infected adults were observed in a HIV care site in Hanoi, and each patient provided 2 DBS cards with whole blood spots and 2 plasma samples. Viral load was measured in DBS and in plasma using the COBAS Ampliprep/TaqMan and the Abbott RealTime assays. To correctly identify those with VL ≥ 1000 copies/mL, sensitivity and specificity were estimated.Results. A total of 198 patients were enrolled. With the Roche technique, 51 plasma VL were ≥1000 copies/mL; among these, 28 presented a VL in DBS that was also ≥1000 copies/mL (sensitivity, 54.9; 95% confidence interval [CI], 40.3–68.9). On the other hand, all plasma VL < 1000 copies/mL were also <1000 copies/mL in DBS (specificity, 100; 95% CI, 97.5–100). With the Abbott technique, 45 plasma VL were ≥1000 copies/mL; among these, 42 VL in DBS were also ≥1000 copies/mL (sensitivity, 93.3%; 95% CI, 81.7–98.6); specificity was 94.8 (95% CI, 90.0–97.7).Conclusions. The Abbott RealTime polymerase chain reaction assay provided adequate VL results in DBS, thus allowing DBS use for VL monitoring.

HIV RNA measurement in dried blood spots of HIV-infected patients in Thailand using Abbott m2000 system

“…We assessed the sensitivity of HIV RNA detection in DBS using the cut-off at 1,000 copies/ mL of plasma, the usual cut-off to consider for treatment failure. We found similarly to studies conducted in other settings [5,16,23] a very high sensitivity of Abbott system to detect HIV Table 1. Baseline characteristics of study population.…”

Whatman FTA®cards versus plasma specimens for the quantitation of HIV-1 RNA using two Real-Time PCR assays

“…At the clinical threshold of 1000 copies/mL, sensibility of FTA cards in this study was seen at 78.6% with Roche, which was slightly less than that observed with Abbott assay (Se = 92.3%) and in already most available literature using Whatman 903 ® cards [15,21–24,28]. Inversely, our results were higher than that observed in Vietnam using Whatman 903 ® cards with Roche assay [29]. Additionally, the contribution of HIV cell-associated DNA and RNA could be the reason for slightly lower sensibility for Roche assay.…”

Dried Blood Spot Tests for the Diagnosis and Therapeutic Monitoring of HIV and Viral Hepatitis B and C

“…The filter papers used can also impact on the performances of in vitro diagnosis tests. Among the DBS collection cards available Whatman 903, Munktell TNF or Ahlstrom Grade 226 have been recommended but other cards have also demonstrated good performances (Waters et al, 2007;Rottinghaus et al, 2013;Smit et al, 2014;World Health Organization [WHO], 2014;Taieb et al, 2016). DBS specimens should be considered from a public health perspective, for which the clinical performance of the in vitro laboratory assays is crucial.…”

“…Nevertheless, the variability of the results must be underlined. Sensitivities ranged from less than 80% to almost 100% at the threshold of 1000 HIV RNA/mL recommended by WHO for virological failure, and specificity from less than 60% to nearly 95% for a given test (Smit et al, 2014;World Health Organization [WHO], 2014;Taieb et al, 2016). The viral reservoir of HIV DNA induces a quantification bias when whole blood is used.…”