Disparate detection outcomes for anti-HCV IgG and HCV RNA in dried blood spots

Abstract

Dried blood spots (DBS) expedite the collection, storage and shipping of blood samples, thereby facilitating large-scale serologic studies. We evaluated the sensitivity of anti-HCV IgG testing and HCV-RNA quantitation using freshly prepared and stored DBS derived from HCV-infected patients. Protocols for elution were optimized using DBS prepared from plasma of 52 HCV-infected persons and 51 uninfected persons (control DBS), then applied to DBS from 33 chronic hepatitis C patients that had been stored at -20°C for 5 years (stored DBS). Control and stored DBS, and their corresponding plasma, were processed for anti-HCV IgG testing using the VITROS chemiluminescence assay (CIA) and the HCV 3.0 enzyme immunoassay (EIA) (Ortho-Clinical Diagnostics), and for HCV RNA quantitation by quantitative (q) RT-PCR. HCV genotyping was conducted by nucleotide sequencing. The sensitivity of CIA and EIA in control DBS was 92% and 90%, respectively, compared to 100% and 97%, respectively, in stored DBS. The sensitivity of HCV RNA detection was 88% in control DBS, compared to 36% in stored DBS. Specificity was 100% for all the assays in both control and stored DBS. Genotypes 1, 2 and 3 were detected in 16 (62%), 6 (23.1%), and 4 (15.3%) samples, respectively. Sequences generated from DBS and their corresponding plasma samples were identical. Whereas the sensitivity of anti-HCV IgG detection in stored DBS was equivalent to that in recently prepared DBS, the sensitivity of HCV RNA detection was markedly lower in stored DBS compared to recently prepared DBS. Stored DBS may be reliably used for anti-HCV detection but for HCV-RNA-based testing freshly prepared DBS is preferable to stored DBS.

Dried blood spots, valid screening for viral hepatitis and human immunodeficiency virus in real-life

“…This observation may to some extent be caused by the different starting titers of the samples, resulting in different dilution factors by elution. The results are consistent with other studies, where low DBS sensitivities have been reported, ranging between 70% and 100%, with specificities from 94% to 100%[18,25,26]. In the study by Ross, almost perfect sensitivities and specificities for DBS were observed compared to serum samples; however, DBS were prepared by applying 100 μL of whole blood to generate DBS (Whatman filter paper), a procedure that most likely is not possible with DBS in real-world settings, where we estimated the average amount to be 75 μL.…”

Performance of ANTI‐HCV testing in dried blood spots and saliva according to HIV status

“…Anti‐HCV testing in DBS and saliva demonstrated specificity above 90% in HCV and HIV monoinfected groups, which is similar to previous studies using DBS in chronic HCV cases and studies using the Salivette device in individuals with chronic hepatitis C and HIV‐infected individuals . Although high specificities were observed, assays were less specific in HIV‐infected individuals, as was observed by Visseaux et al [2013] using saliva samples for anti‐HCV testing in an HIV monoinfected group.…”

“…29 Some studies have shown that high-risk populations, such as individuals who have received transfusion and sexually at-risk individuals, may present falsely reactive results for anti-HCV detection, which could be the product of cross-reactivity with other infections, such as HIV or HBV. [30][31][32] Anti-HCV testing in DBS and saliva demonstrated specificity above 90% in HCV and HIV monoinfected groups, which is similar to previous studies using DBS in chronic HCV cases 12,[23][24][25]33 and studies using the Salivette device in individuals with chronic hepatitis C and HIV-infected individuals. 19,27,34,26 25 and 75% for saliva samples 21 when the same protocol for serum samples was used.…”

Evaluation of the Aptima HCV Quant Dx Assay Using Serum and Dried Blood Spots

“…Importantly, the manuscript also demonstrates the utility of Aptima HCV for the detection of HCV RNA in DBSs, as has been shown in previous studies with other NAAT methods (18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30). Though Aptima HCV on DBSs was less analytically sensitive than serum testing and demonstrated a negative bias compared to quantitation in serum, these data are similar to those previously reported for DBSs tested for HCV RNA by CAP/CTM and Abbott m2000 (20,27,28).…”