Comparison of Hepatitis C Virus RNA and antibody detection in dried blood spots and plasma specimens

Abstract

Background Current diagnostic tests for Hepatitis C Virus (HCV) involve phlebotomy and serologic testing for HCV antibodies (anti-HCV) and RNA, which are not always feasible. Dried blood spots (DBS) present a minimally invasive sampling method and are suitable for sample collection, storage and testing. Objectives To assess the utility of DBS in HCV detection, we evaluated the sensitivity and specificity of DBS for anti-HCV and HCV RNA detection compared to plasma specimens. Study design This cross-sectional validation study was conducted in the context of an existing prospective study of HCV in young injection drug users. Blood samples were collected by venipuncture into serum separator tubes (SST) and via finger stick onto Whatman 903® protein-saver cards. Plasma samples and eluates from the DBS were tested for anti-HCV using either a third generation enzyme-linked or chemiluminescent immunoassay (IA), and HCV RNA using discriminatory HCV transcription-mediated amplification assay (dHCV TMA). DBS results were compared to their corresponding plasma sample results. Results 148 participants were tested for anti-HCV and 132 participants were tested for HCV RNA. For anti-HCV, the sensitivity of DBS was 70%, specificity was 100%, positive predictive value (PPV) was 100%, negative predictive value (NPV) was 76% and Kappa was 0.69. For HCV RNA, the sensitivity of DBS was 90%, specificity was 100%, PPV was 100%, NPV was 94% and Kappa was 0.92. Conclusions DBS are sensitive and very specific in detecting anti-HCV and HCV RNA, demonstrate good correlation with plasma results, and have potential to facilitate diagnosis of HCV infection.

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.…”

“…Sensitivity of anti‐HCV detection in saliva was higher than in DBS samples, likely due to the cut‐off value used, since the signal‐to‐cutoff value recommended by the manufacturer was used for DBS and ROC curve analysis for cut‐off determination in saliva samples. Previous studies demonstrated a sensitivity of 70% for DBS and 75% for saliva samples when the same protocol for serum samples was used. On the other hand, the sensitivity of anti‐HCV detection in saliva and DBS was above 90% when alternative cut‐off values were used …”

“…[9][10][11][12][13][14][15] Assays for detecting anti-HCV in DBS and saliva have reported sensitivities ranging from 70% to 100% and specificities from 87.5% to 100%. [12][13][14][15][16][17][18][19][20][21][22][23][24][25] The differences observed are related to the population studied, saliva collection, type of assay, and modifications in cut-off calculation, incubation of sample and sample volume. The influence of HIV infection on anti-HCV testing in saliva samples was previously evaluated, but a low number of individuals were recruited 26 or the influence of HIV viral load and CD4 cell count were not determined.…”