HemaSpot, a Novel Blood Storage Device for HIV-1 Drug Resistance Testing

Abstract

dHemaSpot, a novel dried-blood storage filter device, was used for HIV-1 pol resistance testing in 30 fresh United States blood samples and 54 previously frozen Kenyan blood samples. Genotyping succeeded in 79% and 58% of samples, respectively, improved with shorter storage and higher viral load, and had good (86%) resistance mutation concordance to plasma. D rug resistance is a major challenge to sustained treatment success, particularly in resource-limited settings (RLS) with few antiretroviral therapy (ART) regimens and limited access to virologic monitoring and drug resistance testing (DRT) (1, 2). Availability of these tests is restricted mostly due to cost and expertise.HemaSpot is a novel dried-blood storage device that combines an absorbent paper to hold samples and a desiccant to maintain dryness, within a plastic cartridge (Spot On Sciences, Austin, TX). To date, HemaSpots had only been applied to Leishmania diagnosis via antibody detection in dogs, showing high sensitivity and specificity (3). We examine the potential of HemaSpot use for HIV-1 DRT.HemaSpot DRT was evaluated using fresh blood in the United States study (30 samples from two patients with various storage times and viral load [VL] dilutions) and previously frozen blood in the Kenya study (54 samples from patients failing first-line ART). Sequences were compared to those derived from plasma. Further study design and laboratory and data analysis methods are given in the supplemental material.In the U.S. study, genotyping was successful in 67% (20/30) of HemaSpots at all tested time points, with detectable VL (range, 1,000 to 100,000 copies/ml) (Table 1), 79% with a VL of Ͼ1,000 copies/ml, and 83% with a VL of Ͼ5,000 copies/ml (see Fig. S1 in the supplemental material). Odds of successful genotyping were 23.1 times higher for each 1-log-unit-higher VL (confidence interval [CI], 1.98 to 270.1; P ϭ 0.01). Genotyping success was significantly lower at 2 weeks (50%) of storage compared to 24 h (90%; odds ratio [OR], 0.01; CI, 0.00 to 0.78; P ϭ 0.04) and marginally significantly lower at 4 weeks (60%; OR, 0.03; CI, 0.00 to 1.40; P ϭ 0.075), with very small odds ratios.In the Kenya study (Table 2), genotyping was successful in 35% (19/54) of HemaSpots with detectable VL (range, 110 to 1,175,462 copies/ml) and in 65% (35/54) from paired plasma samples (VL range, 41 to 1,175,462 copies/ml), including all 19 for which HemaSpot genotyping was successful. Using a cutoff VL of Ͼ1,000 copies/ml, genotyping was successful in 58% of HemaSpots (89% in plasma), and for a VL of Ͼ5,000 copies/ml, genotyping was successful in 68% (94% in plasma).Plasma samples had 7.29 times the odds of successful amplification (95% CI, 2.68 to 19.83; P Ͻ 0.001) compared to HemaSpots. Additionally, successful amplification was related to higher VL (OR, 4.50 per 1-log-unit-higher log 10 VL; CI, 2.32 to 8.70; P Ͻ 0.001) and shorter storage time (OR, 0.11 for time of Ͼ8 months versus Յ8 months; 95% CI, 0.03 to 0.41; P ϭ 0.001). The interaction between analyte type and VL was insig...

Evaluation of the efficiency of dried blood spot-based measurement of hepatitis B and hepatitis C virus seromarkers

“…We www.nature.com/scientificreports www.nature.com/scientificreports/ humans were only literature on HIV measurement [14][15][16][17]26 , it was suggested that HBsAg, HBcAb and anti-HCV could also be measured from HemaSpot specimens through this study. This is the first report to measure HBsAg (both qualitatively and quantitatively), HBcAb and anti-HCV from HemaSpot samples.…”

“…Although HemaSpot-HF blood collecting device (Spot on Science Inc., Austin, USA) is a newly developed DBS in recent years, it represents an affordable alternative to serum-based evaluation of viral hepatitis infections. However, there is no report assessing the feasibility of hepatitis virus marker measurements using HemaSpot, and there are very few reports on its effectiveness [14][15][16][17]26 . So far, no report has directly compared the sensitivity of the Whatman903 card with the HemaSpot (another type of DBS) and standard serum analysis [14][15][16][17]26 for measuring hepatitis virus seromarkers.…”

“…However, there is no report assessing the feasibility of hepatitis virus marker measurements using HemaSpot, and there are very few reports on its effectiveness [14][15][16][17]26 . So far, no report has directly compared the sensitivity of the Whatman903 card with the HemaSpot (another type of DBS) and standard serum analysis [14][15][16][17]26 for measuring hepatitis virus seromarkers. As the amount of blood on the punched filter paper of Whatman903 depends on the initial spread of blood on the filter paper and the position of punching, it is difficult to accurately assess the blood volume on the paper and, therefore, the extraction efficiency.…”

Future technologies for monitoring HIV drug resistance and cure

“…There is potential, however, for improvements in DBS; for example, impregnating the filter paper with antioxidants and inhibitors of RNases to preserve HIV RNA templates [39]. Though novel blood storage devices such as HemaSpot (Spot On Sciences, Inc.; Austin, Texas, USA) [40] and Primestore Molecular Transport Media (Longhorn Vaccines and Diagnostics, LLC, Bethesda, Maryland, USA) [41] have improved recovery of HIV nucleic acids over DBS, their cost is too high for widespread use in LMIC. Additional advances in sample throughput could be accomplished by automated sample extraction (e.g.…”

Harnessing the Potential of Emerging Digital Health and Biological Sampling Technologies for Clinical Drug Development: Promise to Reality

“…Blood collection by microsampling approaches, involving collection of small volumes onto absorbent filter paper, can be adapted for collection of samples by the patient in the home‐setting. Dried Blood Spots (DBS) devices such as HemaSpot – HF Blood Collection device, DBS Systems – HemaXis, or HemaPen, and similar sampling approaches, such as Volumetric Absorptive Microsampler (VAMS), or Touch Activated Phlebotomy (TAP) allow the convenience of home‐based blood sampling and ambient temperature shipping/storage of blood samples. The sampling of alternate matrices such as Dried Saliva Spots to enable home sampling has also been reported .…”