Genetic variations in host IL28B links to the detection of peripheral blood mononuclear cells–associated hepatitis C virus RNA in chronically infected patients

Hepatitis C virus (HCV) is mainly hepatotropic; however, several reports document the presence of genomic viral RNA in extrahepatic sites including peripheral blood mononuclear cells (PBMCs). In this study, the presence of HCV RNA was initially evaluated in the plasma and peripheral blood mononuclear cells (PBMCs) of 53 HCV‐infected patients who were treated per protocol. PBMC‐associated HCV RNA was detectable in 79% of patients. Early virological response to combined pegylated interferon‐α (PegIFN) and ribavirin (RBV) therapy in patients with undetectable levels of PBMCs‐associated HCV RNA was 100%, while it was 60% (P = 0.003) in those who had detectable levels of PBMC‐associated HCV RNA. A sustained virological response was observed in 35% of patients with detectable PBMC‐associated HCV RNA, but was 70% in patients with undetectable levels of PBMC‐associated HCV RNA (P = 0.07). In a multivariate analysis incorporating parameters such as HCV genotype, viral load, presence of cirrhosis and absence of PBMC‐associated HCV RNA, a significant relationship was observed between the detection of PBMC‐associated HCV RNA and the sustained virological response (OR 19.4, 95% CI: 2.1–486.2, P = 0.0061). The association between single nucleotide polymorphism (SNP) in IL28B, known predictor of antiviral therapy outcome, and the occurrence of HCV RNA in PBMC in 84 chronically infected patients was then evaluated. Results suggest that the presence of a G allele in rs8099917, known to associate to a poor response to PegIFN/RBV therapy, also predicts an increased association of HCV RNA with PBMC (OR: 3.564; 95% CI: 1.114–11.40, P = 0.0437).     

Cellular immune responses and occult infection in seronegative heterosexual partners of chronic hepatitis C patients

It is unknown whether hepatitis C virus (HCV)-specific cellular immune responses can develop in seronegative sexual partners of chronically HCV-infected patients and whether they have occult infection. Thirty-one heterosexual partners of patients with chronic HCV were studied, fifteen of them with HCV transmission risks. Ten healthy individuals and 17 anti-HCV seropositive patients, without viremia, were used as controls. Virus-specific CD4+ and CD8+ T-cell responses were measured by flow cytometry against six HCV peptides, situated within the nonstructural (NS) proteins NS3, NS4 and NS5, through intracellular detection of gamma interferon (IFN-γ) or interleukin 4 (IL-4) production and CD69 expression. Sexual partners had a higher production of IFN-γ and IL-4 by CD4+ cells against NS3-p124 (P = 0.003), NS5b-p257 (P = 0.005) and NS5b-p294 (P = 0.012), and CD8+ cells against NS3-p124 (P = 0.002), NS4b-p177 (P = 0.001) and NS3-p294 (P = 0.004) as compared with healthy controls. We observed elevated IFN-γ production by CD4+ T cells against NS5b-p257 (P = 0.042) and NS5b-p294 (P = 0.009) in the sexual partners with HCV transmission risks (sexual, professional and familial altogether) than in those without risks. RNA was extracted from peripheral blood mononuclear cells (PBMC), and detection of HCV-RNA positive and replicative (negative) strands was performed by strand-specific real-time PCR. In four sexual partners, the presence of positive and negative HCV- RNA strands in PBMC was confirmed. Hence, we found an HCV-specific cellular immune response as well as occult HCV infection in seronegative and aviremic sexual partners of chronically HCV-infected patients.     

A phase 1, randomized,dose‐ranging study of GS‐5816, a once‐daily NS5A inhibitor,in patients with genotype 1–4 hepatitis C virus

GS‐5816 is an inhibitor of the hepatitis C virus (HCV) NS5A protein that has demonstrated pan‐genotypic activity and a high barrier to resistance in HCV replicon assays. The aim of this study was to evaluate the safety, antiviral activity and pharmacokinetics of once‐daily doses of GS‐5816 in patients with genotype 1–4 HCV infection. Patients with genotype 1–4 HCV infection were randomized to 3 days of GS‐5816 at doses ranging from 5 to 150 mg or placebo. Adverse events were recorded, and plasma samples obtained for analysis of pharmacokinetics, HCV RNA and NS5A sequencing studies. GS‐5816 5–150 mg for 3 days was well tolerated and resulted in rapid declines in HCV RNA that were sustained over the dosing period. In patients treated with the 150 mg dose of GS‐5816, the mean maximal HCV RNA declines were 4.0, 4.0, 4.4, 3.3 and 3.5 log₁₀ IU/mL in patients with genotype 1a, 1b, 2, 3 and 4 HCV infection, respectively. Pretreatment NS5A resistance‐associated polymorphisms were detected in 31% (22/70) of patients. Genotype 1 and 3 HCV‐infected patients without pretreatment NS5A resistance‐associated polymorphisms had greater declines in HCV RNA than patients with resistance‐associated polymorphisms. Plasma pharmacokinetics were supportive of once‐daily dosing. GS‐5816 demonstrated pangenotypic antiviral activity in patients with genotype 1‐4 HCV infection. It will be further evaluated in combination with other pangenotypic direct‐acting antivirals to achieve the goal of developing a well‐tolerated, highly effective treatment for all HCV genotypes.     

Hepatitis C virus lymphotropism: lessons from a decade of studies

The possibility that HCV infects lymphoid cells has been widely discussed. Evidence in favor of HCV tropism for lymphoid cells derives from a series of data including: (1) the higher sensitivity of testing HCVRNA in PBMC than in serum or plasma samples, with possible detection of HCV RNA-positive PBMC in the absence of HCV viremia; (2) short-term cultures of PBMC which yield a significant increase in the amount of viral RNA on stimulation by mitogens; (3) results of “in situ” methods (i.e. in situ hybridization, immunofluorescence); (4) efficient infection of lymphoid cell lines or PBMC from normal individuals; (5) the persistence of HCV RNA in PBMC obtained from HCV-positive subjects and injected into SCID mice; (6) the long-term persistence of HCV RNA in PBMC in spite of HCV RNA negativity of serum and liver in sustained responder patients after therapy.The principal criticisms concerning effective HCV infection of lymphoid cells arise from technical difficulty in identifying HCV RNA replicative intermediate in these elements. Conflicting data may also result from differences in PBMC infection by different genotypes, samples taken at different stages in the disease process and differences in the sensitivity of detection methods, as well as low replication levels and/or proportion of infected PBMC. Interesting available data about HCV lymphotropism, which is possibly important in influencing the natural history of infection, include: (1) possible preferential viral tropism for specific PBMC subsets; (2) different lymphotropism of different viral strains; (3) selection of distinctive viral strains; (4) identification of putative HCV cell receptors; (5) association between determination of HCV lymphatic infection and t(14; 18) translocation.The clinical correlates of HCV lymphotropism are potentially very numerous, including, first, its role in determining HCV-related lymphoproliferative disorders.     

Polyclonal and monoclonal B lymphocytes response in HCV‐infected patients treated with direct‐acting antiviral agents

Hepatitis C virus (HCV) chronic infection can be associated with extrahepatic manifestations such as mixed cryoglobulinaemia and lymphoproliferative disorders that are endowed with increased rates of morbidity and all‐cause mortality. In this study, we used flow cytometry to evaluate the effect of interferon‐free antiviral treatment on peripheral blood lymphocytes in HCV‐infected patients with or without associated lymphoproliferative disorders. Flow cytometry analysis of peripheral blood lymphocytes was performed at baseline and at the end of treatment. In HCV‐infected patients with lymphoproliferative disorders, we evaluated immunoglobulin (Ig) light chain κ/λ ratio variations as a measure of monoclonal B‐cell response to antiviral therapy. Healthy volunteers were enrolled as controls. A total of 29 patients were included, nine with and 20 without lymphoproliferative disorders. Sustained virological response was achieved in 29 of 29 patients. We observed a significant reduction in the B‐cell compartment (39% global reduction) in eight of nine HCV‐infected patients with lymphoproliferative disorders after viral clearance. We recognized the same trend, even if less pronounced, in HCV‐infected patients without lymphoproliferative disorders (9% global reduction). Among HCV‐infected patients with lymphoproliferative disorders, three showed an improvement/normalization of the immunoglobulin light chain ratio, whereas in the remaining six patients monoclonal B cells persisted to be clonally restricted even 1 year after the end of treatment. Our data show that DAAs treatment can be effective in reducing the frequency of pathological B cells in the peripheral blood of HCV‐infected patients affected by HCV‐associated lymphoproliferative disorders; however, monoclonal populations can persist after viral eradication.     

Hepatitis C virus RNA in peripheral blood mononuclear cells: Comparing acute and chronic hepatitis C virus infection

Hepatitis C virus (HCV) can infect peripheral blood mononuclear cells (PBMC) of patients with chronic HCV infection. No data are available on PBMC testing for HCV RNA in acute hepatitis C. This study investigated the presence of HCV RNA in PBMC of patients with acute posttransfusion hepatitis C, compared with those with chronic HCV infection. Nested polymerase chain reaction (PCR) was applied to detect HCV RNA in 111 and 48 paired samples of serum and PBMC of 11 patients with acute posttransfusion hepatitis C and 48 patients with chronic HCV infection, respectively. In patients with acute posttransfusion hepatitis C, HCV RNA was detected in 17 of 29 (59%) and 67 of 82 (82%) serum samples collected during the incubation period and acute phase, respectively. Meanwhile, of the 48 patients with chronic HCV infection, 41 had serum HCV RNA (85%). HCV RNA was not detected in PBMC samples from incubation period or from acute-phase hepatitis, although it was detected in 12 of the 48 PBMC samples of chronically infected patients (25%) P < .005). Of the 12 PBMC specimens positive for positive-stranded HCV RNA, 6 were also positive for negative-stranded HCV RNA. Among patients with chronic HCV infection, HCV infection of PBMC was not related to age, sex, blood transfusion, serum alanine transaminase (ALT) levels, or serum virus titers. In conclusion, HCV infection of PBMC rarely exists in patients with acute hepatitis C. As HCV infection persists, the incidence of HCV infection of PBMC becomes higher. (Hepatology 1996 May;23(5):977-81)     

Rapid immunoassay alone is insufficient for the detection of hepatitis C virus infection among high‐risk population

Rapid testing for HCV has become a routine practice in resource‐limited settings for initial screening. The objective of this study was to evaluate the performance of rapid immunoassay diagnostic test kits for specific and accurate diagnosis of HCV infection among different patient groups in clinical settings of Kolkata, India. Two hundred and fifty‐four randomly selected serum samples of 612 samples reported as HCV nonreactive by rapid immunodiagnostic tests were evaluated for HCV antibody, ELISA and HCV RNA testing for confirmatory diagnosis. 15.74% were HCV seropositive by ELISA, and 11.02% were RNA positive by nested RT‐PCR. Additionally, 15 HCV‐seronegative chronic liver disease patients with high ALT and AST values were screened for HCV RNA, of which five were positive whose viral load ranged from 1.2 × 10² to 4.4 × 10⁶ IU/mL, and the samples belonged to IVDUs and HIV‐co‐infected individuals. The results showed that HCV rapid immunoassay test cannot be solely relied on as an absolute and accurate diagnostic tool for screening infection of HCV particularly in high‐risk group patients such as IVDUs, haemodialysis, thalassaemic and HIV‐co‐infected patients who need HCV screening frequently.     

Evaluation of a hepatitis C virus core antigen assay from venepuncture and dried blood spot collected samples: A cohort study

The global scale‐up of hepatitis C virus (HCV) diagnosis requires simplified and affordable HCV diagnostic pathways. This study evaluated the sensitivity and specificity of the HCV Architect core antigen (HCVcAg) assay for detection of active HCV infection in plasma and capillary whole blood dried blood spots (DBS) compared with HCV RNA testing in plasma (Abbott RealTime HCV Viral Load). Samples were collected from participants in an observational cohort enrolled at three sites in Australia (two‐drug treatment and alcohol clinics and one homelessness service). Of 205 participants, 200 had results across all samples and assay types and 186 were included in this analysis (14 participants receiving HCV therapy were excluded). HCV RNA was detected in 29% of participants ([95% CI: 22.6‐36.1], 54 of 186). The sensitivity of HCVcAg for detection of active HCV infection in plasma was 98.1% (95% CI: 90‐100) and 100% (95% CI: 93‐100) when compared to HCV RNA thresholds of ≥12 and ≥1000 IU/mL, respectively. The sensitivity of the HCVcAg assay for detection of active HCV infection in DBS was 90.7% (95% CI: 80‐97) and 92.5% (95% CI: 82‐98) when compared to HCV RNA thresholds of ≥12 and ≥1000 IU/mL, respectively. The specificity of HCV core antigen for detection of active infection was 100% (95% CI: 97‐100) for all samples and RNA thresholds. These data indicate that the detection of HCVcAg is a useful tool for determining active HCV infection; to facilitate enhanced testing, linkage to care and treatment particularly when testing plasma samples are collected by venepuncture.     

Antibody screening tests variably overestimate the prevalence of hepatitis C virus infection among HIV‐infected adults in Ghana

HIV coinfection with HCV has been poorly studied in sub‐Saharan Africa, and the reliability of available seroprevalence estimates remains uncertain. The study aim was to determine HCV RNA prevalence in HIV‐infected subjects receiving care in Kumasi, Ghana, and relate the findings to HCV antibody detection. From a population of 1520 HIV‐infected adults, all HBsAg‐positive subjects (n = 236) and a random subset of HBsAg‐negative subject (n = 172) were screened for HCV RNA using pooled plasma; positive samples were genotyped by core and NS5B sequencing. HCV antibodies were detected by three commercial screening assays and confirmed by the line immunoassay. HCV RNA was detected in 4/408 subjects (1.0%, 95% confidence interval 0.0–1.9%), comprising 3/236 (1.3%; 0.0–2.8%) HBsAg‐positive and 1/172 (0.6%; 0.0–1.8%) HBsAg‐negative subjects. HCV RNA‐positive subjects showed reactivity in all three antibody screening assays. Among HCV RNA‐negative subjects, 5/67 (7.5%), 5/67 (7.5%) and 19/67 (28.4%) showed antibody reactivity by each screening assay, respectively, including two (3.0%) with reactivity by all three assays. Only one sample (1.5%) had confirmed antibody reactivity by line immunoassay indicating past HCV infection. HCV‐positive subjects (three males, two females) were aged 30–46 years, by questionnaire‐based interview reported surgical procedures and blood transfusion as risk factors for infection. HCV genotypes were 2 (subtypes 2j, 2l, 2k/unassigned) and 1 (subtype unassigned). Without further testing, HCV antibody screening assays variably overestimated HCV prevalence among HIV‐infected subjects in Ghana. These findings inform the interpretation of previous seroprevalence estimates based upon screening assays alone.     

Chronic hepatitis C associated with monoclonal gammopathy of undetermined significance

BACKGROUND: Two patients were admitted to Mie Prefectural General Medical Center and diagnosed as chronic hepatitis C complicated with monoclonal gammopathy of undetermined significance (MGUS). METHODS: The MGUS class were immunoglobulin (Ig)G. The hepatitis C virus (HCV) RNA genotype was Ib. Based on these findings, they were diagnosed as chronic hepatitis C complicated with MGUS. RESULTS: Histological studies showed chronic hepatitis in the liver and a mild rise in plasma cells without dysplasia and abnormalities in the bone marrow. Serum examination for cryoglobulin was negative. CONCLUSION: Chronic HCV infection might play a pathogenic role in the multistage process leading to lymphoproliferative disorders.     

Detection of replicative form of hepatitis C virus RNA in peripheral blood mononuclear cells.

Paired samples of plasma and peripheral blood mononuclear cells (PBMC) from 7 patients with posttransfusion hepatitis C were collected and studied for the presence of replicative forms of hepatitis C virus (HCV). RNA was extracted and tested for both positive and negative strands of HCV RNA by polymerase chain reaction. Positive-strand RNA of HCV was found in both plasma and PBMC of all 7 patients. However, negative-strand RNA was found in PBMC of 3 patients while none was found in the plasma. Levels of negative-strand RNA were about 10-100 times less than those of positive-strand RNA by semiquantification with serial dilution of viral cDNA. The results suggest that active infection and replication of HCV in PBMC is present in patients with posttransfusion hepatitis C and implicate the extrahepatic infection of HCV.     

EBV体外转化丙型肝炎病人PBMC中HCV持续存在的研究

丙型肝炎病毒(hepatitis c virus,HCV)感染的一个主要特征是病程慢性化并迁延发展。近年越来越多的研究显示,HCV感染单个核细胞在疾病发展过程中起着不容忽视的作用,与干扰素治疗后丙型肝炎的复发关系密切。HCV不仅具有亲肝细胞性,也有淋巴细胞嗜性。丙型肝炎病人外周血单个核细     

Hepatitis C virus long‐term persistence in peripheral blood mononuclear cells in patients with haemophilia. Detection of occult genotype 1

Peripheral blood mononuclear cells (PBMC) from chronic hepatitis C virus‐infected persons can harbour viral variants that are not detected in plasma samples. We explored the presence and persistence of HCV genotypes in plasma and PBMC cultures from 25 HCV‐monoinfected and 25 HIV/HCV‐coinfected patients with haemophilia. Cell cultures were performed at different time points between 1993 and 2010‐2011, and the HCV genome was examined in culture supernatants. Sequential plasma samples were studied during the same time period. Analysing sequential plasma samples, 21% of patients had mixed‐genotype infections, while 50% had mixed infections determined from PBMC culture supernatants. HIV coinfection was significantly associated with the presence of mixed infections (OR = 4.57, P = 0.02; 95% CI = 1.38–15.1). In our previous study, genotype 1 was found in 72% of 288 patients of this cohort. Similar results were obtained with the sequential plasma samples included in this study, 69% had genotype 1. However, when taking into account plasma samples and the results from PBMC supernatants, genotype 1 was identified in 94% of the population. The PBMC‐associated variants persisted for 10 years in some subjects, emphasizing their role as long‐term reservoirs. The presence of genotype 1 in PBMC may be associated with therapeutic failure and should not be disregarded when treating haemophilic patients who have been infected by contaminated factor concentrates. The clinical implications of persistent lymphotropic HCV variants deserve further examination among multiple exposed groups of HCV‐infected patients.     

Low‐level hepatitis C viremia and humoral immune response to NS4 in chronic hepatitis B virus‐hepatitis C virus coinfection

Background: There is a limited amount of published data on the interference of hepatitis B virus (HBV) on hepatitis C virus (HCV). The aim of this study was to investigate the effect of concurrent HBV infection on serum titers of HCV RNA and HCV antibody profiles in chronic HCV infection. Methods: The clinical and virological profiles (serum titers of HCV RNA, HCV genotypes and antibody profiles) of 25 patients with chronic HBV‐HCV coinfection were compared with those of 25 age‐ and sex‐matched patients with HCV infection alone. Results: Among the 25 patients with HBV‐HCV coinfection, only 3 were found hepatitis Be antigen (HBeAg) and HBV DNA positive by hybridization assays, and the other 11 were found HBV DNA positive by polymerase chain reaction. Genotype 1b was dominant in both HBV‐HCV coinfection and HCV infection alone (64% versus 84%, P?>?0.1). Patients with HBV‐HCV coinfection had significantly lower alanine aminotransferase (ALAT) levels and inflammatory scores but higher fibrosis scores than those with HCV infection alone. Serum titers of HCV RNA were significantly lower in HBV‐HCV coinfection than in HCV infection alone. The frequency and relative intensity of antibody response to core, E2/NS1, NS3, and NS5 showed no significant difference between the two groups, but antibody response to NS4 was diminished significantly in HBV‐HCV coinfection. Conclusions: In HBV‐HCV coinfection, serum levels of HBV DNA are usually low or undetectable. Concurrent HBV infection, however, could interfere with HCV replication and suppress antibody response to NS4. The biological significance of selective inhibition of humoral immune response to NS4 in HBV‐HCV coinfection should be further studied.     

Hepatitis C virus 5′ untranslated region variability correlates with treatment outcome

Hepatitis C virus (HCV) variability affects viral–host interactions. We analysed HCV 5′untranslated region (5′UTR) in sera and peripheral blood mononuclear cells (PBMC) from chronic hepatitis C patients undergoing antiviral treatment. We studied 139 patients treated with pegylated interferon and ribavirin. The primary endpoint was a sustained virological response (SVR) defined as negative HCV RNA level 24 weeks after the end of therapy. 5′UTR was analysed by single‐strand conformational polymorphism (SSCP) and sequencing. The pretreatment SSCP pattern in serum and PBMC differed in 26 (18.7%) patients. During therapy, the SSCP pattern remained stable in 65 (60.8%) patients, number of bands declined in 16 (15.0%), and in 18 (16.8%) patients, changes were qualified as ‘shift’ indicating change in band positions. In univariate analysis, there was a significant (P ≤ 0.05) positive association between SVR and pretreatment serum and PBMC dissimilarities, initial viral load <10⁶ IU/mL, IL‐28B CC genotype of the rs12979860 single nucleotide polymorphism and change in the SSCP band pattern (either ‘shift’ or decline) In multivariable analysis, only low initial viral load, IL‐28B genotype, and changes in the SSCP band pattern were independent factors associated with SVR. In conclusion, stability of 5′UTR correlated with infection persistence, while changes correlated with SVR.     

Time to viral suppression is not related to achievement of SVR12 in HCV GT1‐infected patients treated with ombitasvir/paritaprevir/ritonavir and dasabuvir with or without ribavirin

High rates of sustained virologic response at post‐treatment week 12 (SVR12) were achieved in six phase 3 trials of ombitasvir (OBV, an NS5A inhibitor), paritaprevir (an NS3/4A protease inhibitor) co‐dosed with ritonavir (PTV/r) + dasabuvir (DSV, an NS5B RNA polymerase inhibitor) (ie, 3D regimen) with or without ribavirin (RBV) in adults with chronic genotype (GT) 1 hepatitis C virus (HCV) infection. We assessed whether time to first HCV RNA value below the lower limit of quantification in patients with and without cirrhosis was associated with achievement of SVR12. Data were analysed from GT1‐infected patients enrolled in six phase 3 studies of 3D ± RBV. Patients who experienced non‐virologic failure were excluded from analysis. HCV RNA was determined using the Roche COBAS TaqMan RT‐PCR assay (lower limit of quantification, LLOQ =25 IU/mL). SVR12 was analysed by week of first HCV RNA suppression, defined as HCV RNA <LLOQ. The analysis included a total of 2027 patients. Cumulative proportions of subjects with initial HCV RNA suppression <LLOQ at weeks 1, 2, 4 and 6 were 31%, 81%, 99% and 100%, respectively. SVR12 was achieved by 98%, 97%, 98% and 92% of patients with initial suppression at Weeks 1, 2, 4 and 6, respectively (P=.42, trend test). Across six phase 3 trials of 3D ± RBV, most patients achieved viral suppression by week 2. Time to viral suppression was not associated with subsequent achievement of SVR12, suggesting that on‐treatment virologic monitoring may not be necessary with this regimen.     

Evolution of the HCV viral population from a patient with S282T detected at relapse after sofosbuvir monotherapy

Clinical phase II/III studies of the nucleotide analogue HCV NS5B inhibitor sofosbuvir (SOF) have demonstrated high efficacy in HCV‐infected patients in combination therapy. To date, resistance to SOF (S282T in NS5B) has rarely been detected in patients. In this study, we investigated the evolution of S282T viral variants detected in one HCV genotype 2b‐infected patient who relapsed following 12 weeks of SOF monotherapy. Deep sequencing of the NS5B gene was performed on longitudinal plasma samples at baseline, days 2 and 3 on SOF, and longitudinal samples post‐SOF treatment through week 48. Intrapatient HCV evolution was analysed by maximum‐likelihood phylogenetic analysis. Deep sequencing analysis revealed a low level pre‐existence of S282T at 0.05% of viral sequences (4/7755 reads) at baseline and 0.03% (6/23 415 reads) at day 2 on SOF. Viral relapse was detected at week 4 post‐treatment where 99.8% of the viral population harboured S282T. Follow‐up analysis determined that S282T levels diminished post‐treatment reaching undetectable levels 24–48 weeks post‐SOF. Phylogenetic analysis together with the persistence of unique post‐treatment mutations in all post‐SOF samples suggested that growth of wild type resulted from reversion of the S282T mutant to a wild type and not outgrowth of the baseline wild‐type population. Our data suggest that a very low level of pre‐existing S282T at baseline in this patient was enriched and transiently detected following SOF monotherapy. Despite relapse with drug resistance to SOF, this patient was successfully retreated with SOF plus ribavirin for 12 weeks and is now cured from HCV infection.     

Predictive factors for not undergoing RNA testing in patients found to have hepatitis C serology and impact of an automatic alert

The process of diagnosis and linkage to care in cases of hepatitis C virus (HCV) infection remains an obstacle to disease control. The aims of this study were to evaluate predictive factors for not undergoing RNA testing among patients with positive HCV serology and impact of incorporating an automated electronic alert with recommendations in clinical practice. We collected HCV antibody tests requested from October 2011 to September 2014 to evaluate the rate of RNA testing and predictive factors for not undergoing RNA testing. Since October 2014, an automated alert notification has been implemented to remind physicians for testing RNA after a positive HCV test and referral to specialist care. 41 403 HCV antibody tests were requested from 34 073 patients. 870 (2.55%) patients tested positive. After a median of follow‐up of 57.0 months (range 45.6‐82.1), 37.6% did not have RNA testing. The independent predictors for not undergoing RNA testing were primary care serology requests (P < 0.001), no history of drug use (P = 0.005) and a lack of social support (P = 0.015). The intervention impact was evaluated in a pre‐alert cohort (October 2011‐September 2014) and a post‐alert cohort (October 2014‐September 2015). After the incorporation of the alert, the rate of RNA testing increased from 62.4% to 77.7% (P < 0.001). Incomplete assessment of HCV infection is a challenge in primary care. The implementation of an automated alert for recommending RNA testing after a positive HCV antibody test is feasible in clinical practice and increases the rate of patients with RNA testing.