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

Development of simple, rapid, and sensitive methods for detection of hepatitis C virus RNA from whole blood using reverse transcription loop-mediated isothermal amplification

Hepatitis C virus (HCV) infection is an underdiagnosed global health problem. Diagnosis of current HCV infections typically requires testing for HCV RNA using high-complexity laboratory tests. Methods for the detection of HCV RNA that are simple, inexpensive, rapid, and compatible with use outside of a laboratory setting are very important in order to improve access to hepatitis C diagnostic testing and facilitate accelerated linkage to care. We developed and evaluated three simple workflows for extracting HCV RNA from small volumes of whole blood for use in a sensitive, pan-genotypic RT-LAMP assay. The water workflow uses osmotic stress to release HCV RNA and has a limit of detection of 4.3 log10(IU/mL) (95% CI 4.0-4.9). The heat workflow uses a heating step to release HCV RNA and has a limit of detection of 4.2 log10(IU/mL) (95% CI 3.8-5.1). The bead workflow, which uses chemical lysis of the sample and a streamlined paramagnetic solid phase reversible immobilization bead procedure for nucleic acid purification, has a limit of detection of 2.8 log10(IU/mL) (95% CI 2.5-3.4). When used to test whole blood spiked with HCV RNA-positive plasma samples in which most HCV levels were below 5.0 log10(IU/mL), the water, heat, and bead workflows detected HCV RNA in 69%, 75%, and 94% of samples, respectively. These workflows are compatible with visual lateral flow dipsticks, and each takes less than 60 min from sample to result. Each workflow can be performed with minimal and inexpensive equipment. With further procedural simplifications, these workflows may form the basis of assays for the point-of-care diagnosis of HCV infections.

Impact of storage time in dried blood samples (DBS) and dried plasma samples (DPS) for point-of-care hepatitis C virus (HCV) RNA quantification and HCV core antigen detection

The scale-up of hepatitis C virus (HCV) diagnosis and treatment requires affordable and simple tools to improve access to care, especially in low- and middle-income settings with limited infrastructure or high-risk populations. Dried blood and plasma samples (DBS and DPS) are useful alternative for hepatitis C detection in settings lacking adequate infrastructure. We evaluated the performance of DBS and DPS vs plasma in a point-of-care HCV RNA quantitative assay (Xpert HCV Viral Load-Cepheid), and compared HCV core antigen (HCVcAg) detection by the Architect HCV core antigen assay (Abbott) in DBS vs serum. The dried samples were stored at room temperature for different storage times to reproduce the time from sampling to testing in settings with centralized diagnosis or when testing mobile populations. HCV RNA quantification in DBS and DPS presented 100% sensitivity and specificity and a high correlation for up to 3 months of storage. HCV viremia showed a mean decrease of 0.5 log10 IU/mL (DBS) and 0.3 log10 IU/mL (DPS) for storage times up to 1 month. Architect HCVcAg detection presented high sensitivity/specificity (96%/100%) in DBS tested immediately after sampling, decreasing to 86% sensitivity after 7 days of storage. However, sensitivity increased when an optimized cut-off was applied for each storage time. We conclude that DBS and DPS are suitable samples for HCV RNA detection and quantification, being DPS more reliable for shorter storage times. DBS can be also used for HCVcAg qualitative detection and the sensitivity can be increased when adjusting the cut-off values. IMPORTANCE Hepatitis C infection remains a global burden despite the effectiveness of antivirals. In the WHO roadmap to accomplish HCV elimination by 2030, HCV diagnosis is one of the main targets. However, identifying patients in resource-limited settings and high-risk populations with limited access to healthcare remains a challenge and requires innovative approaches that allow decentralized testing. The significance of our research is in verifying the good performance of dried samples for HCV diagnosis using two different diagnostics assays and considering the effect of room temperature storage in this sample format. We confirmed dried samples are an interesting alternative for HCV screening and reflex testing in resource-limited settings or high-risk populations.

Dried blood spot is the feasible matrix for detection of some but not all hepatitis B virus markers of infection

Objective

Use of dried blood spots (DBS) for detection of hepatitis B virus (HBV) markers of infection has the potential to facilitate diagnosis of HBV infection especially in resource-limited countries. The aim of this study was to evaluate the feasibility of DBS for detection of various markers of HBV infections.

Results

Fifty-four DBS samples were engineered from well-characterized plasma samples. All DBS samples were tested for HBsAg, total anti-HBc and HBV DNA, 20 of 54 samples were also tested for HBeAg using commercially available assays. HBsAg was detected in 24 of 25 (96%), HBV DNA in 22 of 25 (88%), total anti-HBc in all 9 (100%), and HBeAg in all 7 (100%) DBS samples. The average difference in HBV DNA levels between DBS eluates and corresponding plasma samples was 2.7 log₁₀ IU/mL. Fifteen DBS eluates positive for HBV DNA were sequenced and all of them belonged to HBV genotype A. Thirteen samples which were negative for all HBV markers showed HBeAg false positivity. Therefore, DBS is a reliable sample matrix for detection of HBsAg, total anti-HBc and HBV DNA, but not HBeAg. Further feasibility studies of DBS for diagnostic purposes and epidemiologic studies are warranted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-022-06178-x.

Laboratory-based testing for hepatitis C infection using dried blood spot samples: A systematic review and meta-analysis of diagnostic accuracy

The use of dried blood spot (DBS) samples can facilitate the implementation of reflex testing by circumventing the need for centrifugation and freezing of venous blood samples. This systematic review assessed the accuracy of using DBS samples to diagnose chronic hepatitis C virus (HCV) infection. A comprehensive search was undertaken to identify articles published up to July 2020 evaluating the diagnostic accuracy of anti-HCV, HCV-RNA and HCV core antigen tests using DBS. Screening, data extraction, quality appraisal and Grading of Recommendations, Assessment, Development and Evaluations certainty of the evidence assessment were performed independently by two reviewers. Meta-analysis, meta-regression and sensitivity analyses were conducted. The evidence demonstrates that laboratory-based anti-HCV and HCV-RNA tests using DBS samples have high diagnostic accuracy. All comparisons were between DBS and venous samples. For the detection of anti-HCV, sensitivity was 95% (95% CI: 92%-97%) and specificity was 99% ([95% CI: 98%-99%]; n = 25; I²  = 81%; moderate certainty). For the detection of HCV-RNA, the sensitivity was 95% (95% CI: 93%-97%) and specificity was 97% ([95% CI: 94%-98%]; n = 20; I²  = 52%; moderate certainty). The sensitivity of HCV core antigen tests was 86% (95% CI: 79%-91%) and specificity was 98% ([95% CI: 94%-99%]; n = 5; I²  = 37%; low certainty) compared with HCV-RNA (the gold standard for detecting chronic HCV). DBS samples could facilitate diagnosis of chronic HCV infection as the necessary sequential tests (anti-HCV and then HCV-RNA or HCV core antigen) can be undertaken using the same blood sample. This could reduce loss of patient follow-up and support international efforts towards HCV elimination in both high and low prevalence settings.

Reliability of dried blood spot (DBS) cards in antibody measurement: A systematic review

BACKGROUND

Increasingly, vaccine efficacy studies are being recommended in low-and-middle-income countries (LMIC), yet often facilities are unavailable to take and store infant blood samples correctly. Dried blood spots (DBS), are useful for collecting blood from infants for diagnostic purposes, especially in low-income settings, as the amount of blood required is miniscule and no refrigeration is required. Little is known about their utility for antibody studies in children. This systematic review aims to investigate the correlation of antibody concentrations against infectious diseases in DBS in comparison to serum or plasma samples that might inform their use in vaccine clinical trials.

METHODS AND FINDINGS

We searched MEDLINE, Embase and the Cochrane library for relevant studies between January 1990 to October 2020 with no language restriction, using PRISMA guidelines, investigating the correlation between antibody concentrations in DBS and serum or plasma samples, and the effect of storage temperature on DBS diagnostic performance. We included 40 studies in this systematic review. The antibody concentration in DBS and serum/plasma samples reported a good pooled correlation, (r2 = 0.86 (ranged 0.43 to 1.00)). Ten studies described a decline of antibody after 28 days at room temperature compared to optimal storage at -20°C, where antibodies were stable for up to 200 days. There were only five studies of anti-bacterial antibodies.

CONCLUSIONS

There is a good correlation between antibody concentrations in DBS and serum/plasma samples, supporting the wider use of DBS in vaccine and sero-epidemiological studies, but there is limited data on anti-bacterial antibodies. The correct storage of DBS is critical and may be a consideration for longer term storage.

High prevalence of Hepatitis C Virus infection among people who use crack cocaine in an important international drug trafficking route in Central-West Region Brazil

In this study, the prevalence rate, associated risk factors and genetic diversity of hepatitis C virus (HCV) infection were determined among people who use crack from an international drug trafficking route in Central-West, Brazil. Blood samples were collected from 700 users of crack from Campo Grande and two border cities of Mato Grosso do Sul State and tested for HCV infection using serological and molecular testing methodologies. Anti-HCV was detected in 31/700 (4.5%, 95% CI: 2.9-6.0%) and HCV RNA in 26/31 (83.9%) of anti-HCV positive samples. Phylogenetic analysis of three HCV sub-genomic regions (5'UTR, NS5B and HVR-1) revealed the circulation of 1a (73.9%), 1b (8.7%) and 3a (17.4%) genotypes. Next-generation sequencing and phylogenetic analysis of intra-host viral populations of HCV HVR-1 showed a significant variation in intra-host genetic diversity among infected individuals, with 58.8% composed of more than one sub-population. Bayesian analysis estimated that the most recent common HCV ancestor for strains identified here was introduced to this region after 1975 following expansion of intravenous drug use in Brazil. Multivariate analyses showed that only 'ever having injected drugs' was independently associated with HCV infection. These results indicate an increasing spread of multiple HCV strains requiring public health intervention, such as harm reduction, testing services and treatment among crack users in this important border region of Central Brazil.

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

Although hepatitis B (HBV) and C (HCV) virus infections are still global health issues, measuring sero-markers by standard venipuncture is challenging in areas limited with the adequate human resources and basic infrastructure. This study aimed to inform the usefulness of dried blood spot (DBS) sampling technique for epidemiological study of HBV and HCV in the resources limited areas. We compared specimen recovery rate expressed as analytical sensitivity ratio of HBsAg, HBcAb and anti-HCV between serum specimens and DBS samples (HemaSpot vs Whatman903). Sensitivity ratio was calculated as the ratio of the measured value from DBS to the measured value from serum. Then both the qualitative and quantitative comparisons of HBsAg detection by DBS were done using Cambodian samples. HBsAg, HBcAb and anti-HCV sensitivity ratios for the highest sample dilution (8-fold) were 31.2:1, 38.9:1 and 32.0:1 for Whatman903 card and 17.6:1, 23.5:1 and 26.3:1 for HemaSpot respectively. Detection efficacy of HemaSpot (80%) was not inferior to Whatman903 (60%) after 1 month storage, and no significant difference in any hepatitis virus sero-markers was observed in HemaSpot-spotted patient samples stored for 2 weeks at −25 °C and 29 °C. All reference HemaSpot -spotted 400 HBsAg sero-negative samples showed negative. Sensitivity and specificity of HBsAg in HemaSpot were 92.3% and 100%. The recovery expressed as analytical sensitivity ratio of HBsAg, HBcAb and anti-HCV of HemaSpot specimen were not inferior to Whatman903. Therefore, DBS with its usefulness proved as an acceptable tool for large epidemiological study of HBV and HCV in resources limited remote area.

Evaluation of the diagnostic accuracy of laboratory-based screening for hepatitis C in dried blood spot samples: A systematic review and meta-analysis

The dried blood spot (DBS) is increasingly used for the hepatitis C virus (HCV) screening. Our objective was to perform a meta-analysis of the methodology for HCV screening in DBS samples, particularly in the type of diagnostic assay used. We performed a meta-analysis of all eligible studies published to date (March 2018). The literature search revealed 26 studies: 21 for detection of anti-HCV antibodies and 10 for detection of HCV-RNA. Statistical analyses were performed using Meta-DiSc and STATA (MIDAS module). For detection of HCV antibodies, pooled diagnostic accuracy measures were as follows: sensitivity 96.1%, specificity 99.2%, positive likelihood ratio (PLR) 105, negative likelihood ratio (NLR) 0.04, diagnostic odds ratio (DOR) 2692.9, and summary receiver operating characteristic (SROC) 0.997 ± 0.001. For detection of HCV-RNA, the pooled diagnostic accuracy measures were as follows: sensitivity 97.8%, specificity 99.2%, PLR 44.8, NLR 0.04, DOR 1966.9, and SROC 0.996 ± 0.013. Similar values of pooled diagnostic accuracy measures were found according to the type of anti-HCV antibody detection assay (enzyme-linked immunosorbent assay, rapid diagnostic test, and chemiluminescence assays) and HCV-RNA detection assay (real-time polymerase chain reaction and transcription-mediated amplification). The analysis of external validity showed a high negative predicted value (NPV) for both approaches, but a low positive predicted value (PPV) when prevalence was < 10%, particularly in HCV-RNA tests. Finally, this meta-analysis is subject to limitations, especially publication bias and significant heterogeneity between studies. In conclusion, HCV screening in DBS samples has an outstanding diagnostic performance, with no relevant differences between the techniques used. However, external validity may be limited when the HCV prevalence is low.

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

Hepatitis C virus (HCV) RNA quantitation is the primary method by which active HCV infections are identified and the response to direct-acting antiviral therapy is monitored. This study describes the evaluation of the Aptima HCV Quant Dx assay (Aptima HCV) performed on the Panther system. The clinical performance of Aptima HCV was compared to that of the Cobas AmpliPrep/Cobas TaqMan HCV test v2.0 (CAP/CTM). Overall agreement was 84.9% (186/219) with a kappa statistic of 0.755 (standard error, 0.037; 95% confidence interval [CI], 0.682 to 0.828). Passing-Bablok regression of log₁₀ IU/ml values revealed a regression line of Y = 1.163 × X - 0.991 (95% CI of the slope, 1.103 to 1.221, and intercept, -1.341 to -0.642). The 95% lower limit of detection (LLOD) for Aptima HCV on dried blood spot (DBS) samples was calculated to be 2.43 log₁₀ IU/ml (267 IU/ml; 95% CI, 2.31 to 2.73 log₁₀ IU/ml [204 to 540 IU/ml]). A comparison of Aptima HCV testing on paired DBS and serum specimens collected from patients at the time of routine blood collection for CAP/CTM demonstrated an overall agreement of 90.1% (82/91) with a kappa statistic of 0.657 (standard error, 0.101; 95% CI, 0.458 to 0.855). In conclusion, Aptima HCV provides a suitable alternative for HCV RNA testing on serum and DBS samples.

What Is Needed to Eliminate Hepatitis B Virus and Hepatitis C Virus as Global Health Threats

Hepatitis B virus (HBV) and hepatitis C virus (HCV) cause 1.3 million deaths annually. To prevent more than 7 million deaths by 2030, the World Health Organization set goals to eliminate HBV and HCV, defined as a 90% reduction in new infections and a 65% reduction in deaths, and prevent more than 7 million related deaths by 2030. Elimination of HBV and HCV is feasible because of characteristics of the viruses, reliable diagnostic tools, and available cost-effective or cost-saving interventions. Broad implementation of infant immunization against HBV, blood safety, and infection-control programs have greatly reduced the burden of HBV and HCV infections. To achieve elimination, priorities include implementation of HBV vaccine-based strategies to prevent perinatal transmission, safe injection practices and HCV treatment for persons who inject drugs, and testing and treatment for HBV- and HCV-infected persons. With sufficient capacity, HBV and HCV elimination programs can meet their goals.

Dried Blood Spots for Global Health Diagnostics and Surveillance: Opportunities and Challenges

There is increasing interest in using dried blood spot (DBS) cards to extend the reach of global health and disease surveillance programs to hard-to-reach populations. Conceptually, DBS offers a cost-effective solution for multiple use cases by simplifying logistics for collecting, preserving, and transporting blood specimens in settings with minimal infrastructure. This review describes methods to determine both the reliability of DBS-based bioanalysis for a defined use case and the optimal conditions that minimize pre-analytical sources of data variability. Examples by the newborn screening, drug development, and global health communities are provided in this review of published literature. Sources of variability are linked in most cases, emphasizing the importance of field-to-laboratory standard operating procedures that are evidence based and consider both stability and efficiency of recovery for a specified analyte in defining the type of DBS card, accessories, handling procedures, and storage conditions. Also included in this review are reports where DBS was determined to not be feasible because of technology limitations or physiological properties of a targeted analyte.

Determination of anti-HCV and quantification of HCV-RNA and IP-10 from dried blood spots sent by regular mail

BACKGROUND

With the introduction of direct acting antivirals, treatment of hepatitis C virus (HCV) in hard-to-reach populations is now feasible. Therefore, new cost-effective and reliable test methods are needed. Determination of HCV antibodies and HCV-RNA from dried blood spots samples could represent one such method. Here we examined whether anti-HCV could be detected-and HCV-RNA quantified-from dried blood spots, sent by regular mail. We also investigated, if IP-10 determined from dried blood spots correlated with fibrosis progression appraised by transient elastography.

METHOD

Forty chronic HCV infected patients were consecutively enrolled. At baseline and after six months, dried blood spots were prepared from blood collected by venous puncture, dried for 4-6 hours, then stored in gas-impermeable plastic bags with a desiccator, before being sent by regular mail. At each visit, approximately six months apart, paired venous samples was obtained and analyzed for anti-HCV, HCV-RNA and IP-10.

RESULTS

Anti-HCV was found in 66/67 of the dried blood spots. Sixty-six paired samples were available for HCV-RNA analysis. A statistically significant correlation was found between log HCV-RNA concentrations in plasma, and log HCV-RNA obtained from (P < 0.0001, Pearson's R 0.6788, R2 0.4607). HCV-RNA, derived from DBS samples, was lower than the corresponding plasma concentration, reflected by a Bland-Altman bias of 3 with SD of bias ± 0.6472. We found no correlation between IP-10 and fibrosis progression.

CONCLUSIONS

We identified anti-HCV in 66/67samples, and quantified IP-10 and HCV-RNA from dried blood spots, dried at room temperature and sent by regular mail. HCV-RNA concentrations from the dried blood spots were lower than corresponding plasma values; a probable result of heparin coated test tubes. We found no correlation between IP-10 and fibrosis progression. Overall, dried blood spots could be a cost-effective and easy-to-use alternative to standard tests for the diagnosis of HCV infections.

Community-based screening of hepatitis C with a one-step RNA detection algorithm from dried-blood spots: Analysis of key populations in Barcelona, Spain

Alternative strategies are required to enhance the diagnosis of silent hepatitis C virus (HCV) infections in key populations at risk. Among them, HCV prevalence and bio-behavioural data are scarce for HIV-negative men who have sex with men (MSM) and men and trans-women sex workers. We sought to describe and assess the potential benefits of a community-based one-step HCV screening and confirmatory strategy for these populations in Barcelona. The screening strategy based on a real-time RT-PCR assay for HCV-RNA detection in dried-blood spots (DBS) was validated and implemented in addition to an antibody point-of-care test in a community centre. HCV prevalence was assessed, and bio-behavioural data were collected. The molecular assay was precise, reproducible, sensitive and specific. Four HIV-negative MSM reported being currently infected (0.75% HCV self-reported prevalence). Implementation of DBS testing was easy, and acceptability was >95%, but no silent HCV case was diagnosed (N = 580). High-risk sexual practices and drug use for sex were reported frequently. HIV prevalence was 4.7% in MSM and 10% in sex workers. Self-reported prevalence of other STIs ranged from 11.3% to 36.2%. In conclusion, HCV-RNA testing in DBS showed a good performance, but the assessed one-step strategy does not seem beneficial in this setting. Although no silent HCV infections were detected, the observed high-risk behaviours and prevalence of other STIs suggest that HCV spread should be periodically monitored among these populations in Barcelona by means of behavioural surveillance, rapid antibody testing and molecular confirmation in DBS.

Evaluation of dried blood spot samples for screening of hepatitis C and human immunodeficiency virus in a real-world setting

Both hepatitis C virus (HCV) infection and human immunodeficiency virus (HIV) infection are underdiagnosed, particularly in low-income countries and in difficult-to-access populations. Our aim was to develop and evaluate a methodology for the detection of HCV and HIV infection based on capillary dry blood spot (DBS) samples taken under real-world conditions. We carried out a cross-sectional study of 139 individuals (31 healthy controls, 68 HCV-monoinfected patients, and 40 HCV/HIV-coinfected patients). ELISA was used for anti-HCV and anti-HIV antibody detection; and SYBR Green RT-PCR was used for HCV-RNA detection. The HIV serological analysis revealed 100% sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). The HCV serological analysis revealed a sensitivity of 92.6%, specificity of 100%, PPV of 100%, and NPV of 79.5%. Finally, the HCV-RNA detection test revealed a detection limit of 5 copies/µl with an efficiency of 100% and sensitivity of 99.1%, specificity of 100%, PPV of 100%, and NPV of 96.9%. In conclusion, our methodology was able to detect both HCV infection and HIV infection from the same DBS sample with good diagnostic performance. Screening for HCV and HIV using DBS might be a key strategy in the implementation of national programs for the control of both infections.

Diagnostic accuracy of serological diagnosis of hepatitis C and B using dried blood spot samples (DBS): two systematic reviews and meta-analyses

BACKGROUND

Dried blood spots (DBS) are a convenient tool to enable diagnostic testing for viral diseases due to transport, handling and logistical advantages over conventional venous blood sampling. A better understanding of the performance of serological testing for hepatitis C (HCV) and hepatitis B virus (HBV) from DBS is important to enable more widespread use of this sampling approach in resource limited settings, and to inform the 2017 World Health Organization (WHO) guidance on testing for HBV/HCV.

METHODS

We conducted two systematic reviews and meta-analyses on the diagnostic accuracy of HCV antibody (HCV-Ab) and HBV surface antigen (HBsAg) from DBS samples compared to venous blood samples. MEDLINE, EMBASE, Global Health and Cochrane library were searched for studies that assessed diagnostic accuracy with DBS and agreement between DBS and venous sampling. Heterogeneity of results was assessed and where possible a pooled analysis of sensitivity and specificity was performed using a bivariate analysis with maximum likelihood estimate and 95% confidence intervals (95%CI). We conducted a narrative review on the impact of varying storage conditions or limits of detection in subsets of samples. The QUADAS-2 tool was used to assess risk of bias.

RESULTS

For the diagnostic accuracy of HBsAg from DBS compared to venous blood, 19 studies were included in a quantitative meta-analysis, and 23 in a narrative review. Pooled sensitivity and specificity were 98% (95%CI:95%-99%) and 100% (95%CI:99-100%), respectively. For the diagnostic accuracy of HCV-Ab from DBS, 19 studies were included in a pooled quantitative meta-analysis, and 23 studies were included in a narrative review. Pooled estimates of sensitivity and specificity were 98% (CI95%:95-99) and 99% (CI95%:98-100), respectively. Overall quality of studies and heterogeneity were rated as moderate in both systematic reviews.

CONCLUSION

HCV-Ab and HBsAg testing using DBS compared to venous blood sampling was associated with excellent diagnostic accuracy. However, generalizability is limited as no uniform protocol was applied and most studies did not use fresh samples. Future studies on diagnostic accuracy should include an assessment of impact of environmental conditions common in low resource field settings. Manufacturers also need to formally validate their assays for DBS for use with their commercial assays.

Hepatitis C Virus (HCV) RNA screening and sequencing using dry plasma spots

BACKGROUND

HCV RNA screening of large sample repositories provides data on HCV epidemic patterns that may help guide control policies. In resource-limited settings, shipment of frozen samples to molecular laboratory facilities and testing of individual samples may be prohibitively expensive.

OBJECTIVE

Our aim was to detect and sequence HCV RNA in a large HIV-positive cohort from Kumasi, Ghana, using pooled and individual dried plasma spots (DPS) produced from samples stored at -80°C.

STUDY DESIGN

In the validation phase, replicate DPS were prepared with six dilutions (500-10,000 IU/ml) of the 4^th International Standard for HCV and tested in three independent experiments. In the testing phase, DPS prepared with plasma samples from 875 HIV-positive subjects were pooled for screening, followed by testing of individual DPS of positive pools. Input from individual DPS was two 6mm punches; pools comprised two punches from each of five DPS. Genotypes were determined by Sanger sequencing of HCV core and NS5B.

RESULTS

With the dilution series, sensitivity of HCV RNA detection was ≥2500 IU/ml. Replicate DPS gave intra-assay and inter-assay coefficients of variation ≤1.4%. With the stored samples, HCV RNA was detected in 5/175 DPS pools and in one DPS from each positive pool, yielding a HCV RNA prevalence of 5/875 (0.57%; 95% confidence interval 0.07-1.07%). The five samples were sequenced as HCV genotypes 2l and 2r.

DISCUSSION

DPS allowed reproducible HCV RNA detection, and pooling effectively contained the cost and labour of screening a previously untested, low-prevalence cohort. DPS were also suitable for HCV sequencing.

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

The use of saliva and dried blood spots (DBS) could increase access to HCV diagnosis for high-risk populations, such as HIV-infected individuals, but the performance of these assays has not been well established in this group. This study aims to evaluate HIV status, particularly TCD4⁺ cell count and viral load, in the performance of anti-HCV testing using DBS and saliva. A total of 961 individuals classified as HCV+, HIV+, or HIV/HCV+, as well as negative controls, donated serum, DBS, and saliva samples for anti-HCV testing using a commercial enzyme immunoassay. Sample volume was modified for DBS and saliva, and an ROC curve was used for cut-off determination in saliva. Anti-HCV sensitivities were greater than 93% using DBS and saliva in the HCV+ group, while they were 83.3% and 95.6% for HCV/HIV+ individuals for DBS and saliva assays, respectively. Specificity varied from 91.7% to 100% using saliva and DBS in HIV monoinfected and control subjects. When only anti-HCV/HCV RNA+ serum samples, that is, true positives, were considered, the sensitivities were 98.3% and 100% for DBS and saliva, respectively, in the HCV+ group and 91.6% and 94.8% for DBS and saliva, respectively, in the HIV/HCV+ group. High absorbance values were observed among those presenting with HCV RNA in serum and low HIV viral load (less than 50 copies/mL). In conclusion, DBS and saliva samples could be used for anti-HCV detection, particularly to identify active HCV cases, but low sensitivity was observed for anti-HCV testing using DBS in the HIV/HCV+ group.

Who to test and how to test for chronic hepatitis C infection - 2016 WHO testing guidance for low- and middle-income countries

Testing and diagnosis of hepatitis C virus (HCV) infection is the gateway for access to both treatment and prevention services, and crucial for an effective hepatitis epidemic response. In contrast to HIV, a systematic approach to hepatitis C testing has been fragmented and limited to a few countries, and there remains a large burden of undiagnosed cases globally. Key challenges in the current hepatitis testing response, include lack of simple, reliable, and low cost diagnostic tests, laboratory capacity, and testing facilities; inadequate data to guide country-specific hepatitis testing approaches and who to test; stigmatization and social marginalization of some groups with or at risk of viral hepatitis; and lack of international or national guidelines on hepatitis testing for resource-limited settings. New tools to support the hepatitis global response include the 2016 Global Hepatitis Health Sector Strategy which include targets for testing and diagnosis, and World Health Organization (WHO) 2016 hepatitis testing guidelines for adults, adolescents, and children in low- and middle-income countries. The testing guidance complements recent published WHO guidance on the prevention, care and treatment of chronic hepatitis C and hepatitis B infection. These testing guidelines outline the public health approach to strengthening and expanding current testing practices for HCV and HBV and address what serological and virological assays to use, and who to test, as well as interventions to promote linkage to prevention and care after testing. They are intended for use across all age groups and populations. See boxes for key recommendations. Future directions and innovations in viral hepatitis testing include use of point-of-care assays for nucleic acid testing (NAT) and core antigen; validation of dried blood spots specimens with different commercial serological and NAT assays; multiplex and polyvalent platforms for integrated testing of HIV, HBV and HCV; and potential for self-testing.

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

AIM

To detect chronic hepatitis B (CHB), chronic hepatitis C (CHC) and human immunodeficiency virus (HIV) infections in dried blood spot (DBS) and compare these samples to venous blood sampling in real-life.

METHODS

We included prospective patients with known viral infections from drug treatment centers, a prison and outpatient clinics and included blood donors as negative controls. Five drops of finger capillary blood were spotted on filter paper, and a venous blood sample was obtained. The samples were analyzed for HBsAg, anti-HBc, anti-HBs, anti-HCV, and anti-HIV levels as well as subjected to a combined nucleic acid test (NAT) for HBV DNA, HCV RNA and HIV RNA.

RESULTS

Samples from 404 subjects were screened (85 CHB, 116 CHC, 114 HIV and 99 blood donors). DBS had a sensitivity of > 96% and a specificity of > 98% for the detection of all three infections. NAT testing did not improve sensitivity, but correctly classified 95% of the anti-HCV-positive patients with chronic and past infections. Anti-HBc and anti-HBS showed low sensitivity in DBS (68% and 42%).

CONCLUSION

DBS sampling, combined with an automated analysis system, is a feasible screening method to diagnose chronic viral hepatitis and HIV infections outside of the health care system.

Evaluation of dried blood spot samples for hepatitis C virus detection and quantification

BACKGROUND

Dried blood spots (DBS) could be an excellent alternative for HCV diagnosis, since it is less invasive and can be stored and transported without refrigeration.

OBJECTIVES

The aim of this study was to optimize quantitative and qualitative methods for HCV detection in DBS.

STUDY DESIGN

DBS and serum samples were collected from 99 subjects (59 anti-HCV/HCV RNA positive and 40 seronegative samples). Seven extraction methods and different PCR parameters were evaluated in DBS samples in the quantitative RT-PCR (qRT-PCR) developed to amplify the 5' noncoding region of HCV. A qualitative PCR for amplification of NS5B region of HCV was also valued and the nested-PCR sequenced.

RESULTS

The qRT-PCR showed good correlation to commercial assay for HCV viral measurement in serum. To quantify HCV RNA in DBS, it was necessary to increase reverse transcriptase and cDNA concentration. HCV RNA quantification in DBS demonstrated sensitivity of 65.9%, 100% of specificity and kappa statistic of 0.65. The median viral load of DBS samples was 5.38 log10 copies/ml (minimum value=1.76 and maximum value=10.48 log10 copies/ml). HCV RNA was detected in NS5B regions and nucleotide sequences obtained in 43 serum and 11 DBS samples. The presence of the same subtype was observed in paired serum and DBS samples.

CONCLUSIONS

In this study, it was possible to demonstrate that, despite the low sensitivity, the optimized protocol was able to determine the viral load, as well as, the infecting HCV genotype, validating the usefulness of DBS for viral load determination and molecular epidemiology studies of HCV.

Next-Generation Sequencing Reveals Frequent Opportunities for Exposure to Hepatitis C Virus in Ghana

Globally, hepatitis C Virus (HCV) infection is responsible for a large proportion of persons with liver disease, including cancer. The infection is highly prevalent in sub-Saharan Africa. West Africa was identified as a geographic origin of two HCV genotypes. However, little is known about the genetic composition of HCV populations in many countries of the region. Using conventional and next-generation sequencing (NGS), we identified and genetically characterized 65 HCV strains circulating among HCV-positive blood donors in Kumasi, Ghana. Phylogenetic analysis using consensus sequences derived from 3 genomic regions of the HCV genome, 5'-untranslated region, hypervariable region 1 (HVR1) and NS5B gene, consistently classified the HCV variants (n = 65) into genotypes 1 (HCV-1, 15%) and genotype 2 (HCV-2, 85%). The Ghanaian and West African HCV-2 NS5B sequences were found completely intermixed in the phylogenetic tree, indicating a substantial genetic heterogeneity of HCV-2 in Ghana. Analysis of HVR1 sequences from intra-host HCV variants obtained by NGS showed that three donors were infected with >1 HCV strain, including infections with 2 genotypes. Two other donors share an HCV strain, indicating HCV transmission between them. The HCV-2 strain sampled from one donor was replaced with another HCV-2 strain after only 2 months of observation, indicating rapid strain switching. Bayesian analysis estimated that the HCV-2 strains in Ghana were expanding since the 16^th century. The blood donors in Kumasi, Ghana, are infected with a very heterogeneous HCV population of HCV-1 and HCV-2, with HCV-2 being prevalent. The detection of three cases of co- or super-infections and transmission linkage between 2 cases suggests frequent opportunities for HCV exposure among the blood donors and is consistent with the reported high HCV prevalence. The conditions for effective HCV-2 transmission existed for ~ 3–4 centuries, indicating a long epidemic history of HCV-2 in Ghana.

Update on hepatitis B and C virus diagnosis

Viral hepatitis B and C virus (HBV and HCV) are responsible for the most of chronic liver disease worldwide and are transmitted by parenteral route, sexual and vertical transmission. One important measure to reduce the burden of these infections is the diagnosis of acute and chronic cases of HBV and HCV. In order to provide an effective diagnosis and monitoring of antiviral treatment, it is important to choose sensitive, rapid, inexpensive, and robust analytical methods. Primary diagnosis of HBV and HCV infection is made by using serological tests for detecting antigens and antibodies against these viruses. In order to confirm primary diagnosis, to quantify viral load, to determine genotypes and resistance mutants for antiviral treatment, qualitative and quantitative molecular tests are used. In this manuscript, we review the current serological and molecular methods for the diagnosis of hepatitis B and C.