Clinical performance evaluation of four automated chemiluminescence immunoassays for hepatitis C virus antibody detection

Development of a fully automated chemiluminescent immunoassay for the quantitative and qualitative detection of antibodies against African swine fever virus p72

African swine fever (ASF), caused by ASF virus (ASFV), is a highly infectious and severe hemorrhagic disease of pigs that causes major economic losses. Currently, no commercial vaccine is available and prevention and control of ASF relies mainly on early diagnosis. Here, a novel automated double antigen sandwich chemiluminescent immunoassay (DAgS-aCLIA) was developed to detect antibodies against ASFV p72 (p72-Ab). For this purpose, recombinant p72 trimer was produced, coupled to magnetic particles as carriers and labeled with acridinium ester as a signal trace. Finally, p72-Ab can be sensitively and rapidly measured on an automated chemiluminescent instrument. For quantitative analysis, a calibration curve was established with a laudable linearity range of 0.21 to 212.0 ng/mL (R2 = 0.9910) and a lower detection limit of 0.15 ng/mL. For qualitative analysis, a cut-off value was set at 1.50 ng/mL with a diagnostic sensitivity of 100.00% and specificity of 98.33%. Furthermore, antibody response to an ASF gene-deleted vaccine candidate can be accurately quantified using this DAgS-aCLIA, as evidenced by early seroconversion as early as 7 days post-immunization and high antibody levels. Compared with available enzyme-linked immunosorbent assays, this DAgS-aCLIA demonstrated a wider linearity range of 4 to 16-fold, and excellent analytical sensitivity and agreement of over 95.60%. In conclusion, our proposed DAgS-aCLIA would be an effective tool to support ASF epidemiological surveillance.IMPORTANCEAfrican swine fever virus (ASFV) is highly contagious in wild boar and domestic pigs. There is currently no vaccine available for ASF, so serological testing is an important diagnostic tool. Traditional enzyme-linked immunosorbent assays provide only qualitative results and are time and resource consuming. This study will develop an automated chemiluminescent immunoassay (CLIA) that can quantitatively and qualitatively detect antibodies to ASFV p72, greatly reducing detection time and labour-intensive operation, and improving detection sensitivity and linearity range. This novel CLIA would serve as a reliable and convenient tool for ASF pandemic surveillance and vaccine development.

The impact of sofosbuvir/ledipasvir on chronic hepatitis C-infected paediatric patients: a Middle East single-centre experience

Introduction

Direct-acting antiviral (DAA) regimens were approved in 2013 with a response rate exceeding 95% and minimal side effects. The response rate of sofosbuvir and ledipasvir exceeds 95% with minimal side effects.

Aim

To identify the effects of this regimen in the eradication of viruses from the patients.Material and methods: A prospective observational, open-label study took place between July 2018 and September 2020. The study included 37 patients, about two-thirds of them were male 23 (62.16%), while females comprised 14 (37.84%). All patients received a combination of sofosbuvir 400 mg and ledipasvir 90 mg in a single oral daily dose according to their weight.

Results

The most common HCV genotype was HCV-4, followed by HCV-1 and HCV-2. And by comparing parameters at baseline, end of the treatment, and 12 weeks after completing the treatment, the laboratory data revealed dramatic drops of all liver function tests, the mean of alanine aminotransferase (ALT) (31.1 ±1.42 IU/l vs. 95.5 ±23.16, p < 0.05), aspartate aminotransferase (AST) (29.86 ±1.75 IU/l vs. 89.19 ±24.83, p < 0.05), total serum bilirubin (TSB) (0.57 ±0.07 mg/dl vs. 1.73 ±0.38 mg/dl, p < 0.05), mean HCV PCR (1605168 ±368223.72), after finishing the treatment course, and 12 weeks after that it was non-detectable (p < 0.05).

Conclusions

Treatment with dose-adjusted oral DAAs (SOF/LED) for 12 weeks was well tolerated in Iraqi children and adolescents infected with chronic HCV infections, with a high success rate and trivial adverse effects.

Clinical performance of the MAGLUMI Anti-HCV (CLIA) Test for detection of hepatitis C virus antibodies

BACKGROUND

Hepatitis C virus (HCV) infection screening and diagnosis are critical to control the hepatitis C epidemic. Testing for anti-HCV antibodies (Ab) in blood samples is the first step to screen people who have been infected with the virus.

OBJECTIVES

To evaluate the performance of the MAGLUMI Anti-HCV (CLIA) Test for detection of HCV antibodies.

STUDY DESIGN

To assess the diagnostic specificity, serum samples from 5053 unselected donors and 205 blood specimens from hospitalized patients were collected. To evaluate the diagnostic sensitivity, 400 positive HCV Ab samples were collected and 30 seroconversion panels were tested. All samples that met the test criteria were tested with the MAGLUMI Anti-HCV (CLIA) Test according to manufacturer's instruction. Results of the MAGLUMI Anti-HCV (CLIA) Test were compared with the Abbott ARCHITECT anti-HCV reference test.

RESULTS

The specificity of the MAGLUMI Anti-HCV (CLIA) Test was 99.75% and 100.00% in blood donor and hospitalized patient samples, respectively. The sensitivity of the Test in HCV Ab positive samples was 100.00%. Seroconversion sensitivity was comparable between the MAGLUMI Anti-HCV (CLIA) Test and the reference assay.

CONCLUSIONS

The performance of the MAGLUMI Anti-HCV (CLIA) Test makes it suited for HCV infection diagnosis.

The signal-to-cutoff ratios to predict HCV infection among people who inject drugs

People who inject drugs (PWIDs) are primarily the high-risk population for HCV infection. This study aims to determine the optimal cut-off values for predicting HCV infection status based on the Signal-to-Cutoff (S/CO) ratio. In this study, a total of 719 PWIDs’ samples were collected, and performed for screening test by ELISA assay, and followed by RIBA assay and NAT assay to detect HCV antibody and HCV RNA levels, respectively. The findings revealed that the prevalence of HCV infection among PWIDs was 54.66% (393/719), and the false-positive rate of HCV antibody detection by ELISA assay among PWIDs was only 3.85% (16/416). In addition, when the optimal cut-off value for S/CO ratio was 2.0, the sensitivity and specificity of HCV antibody were 100.00% and 93.55%, respectively. And when the optimal cut-off value for S/CO ratio was 21.36, the sensitivity and specificity of HCV RNA positive were 89.90% and 72.73%, respectively. In conclusion, the status of HCV infection can be predicted based on the S/CO ratios of the ELISA assay, which can improve diagnosis and facilitate timely treatment to effectively prevent the spread of HCV infection.

Molecular Probes for Autofluorescence-Free Optical Imaging

Optical imaging is an indispensable tool in clinical diagnostics and fundamental biomedical research. Autofluorescence-free optical imaging, which eliminates real-time optical excitation to minimize background noise, enables clear visualization of biological architecture and physiopathological events deep within living subjects. Molecular probes especially developed for autofluorescence-free optical imaging have been proven to remarkably improve the imaging sensitivity, penetration depth, target specificity, and multiplexing capability. In this Review, we focus on the advancements of autofluorescence-free molecular probes through the lens of particular molecular or photophysical mechanisms that produce long-lasting luminescence after the cessation of light excitation. The versatile design strategies of these molecular probes are discussed along with a broad range of biological applications. Finally, challenges and perspectives are discussed to further advance the next-generation autofluorescence-free molecular probes for in vivo imaging and in vitro biosensors.

Comparative evaluation of Elecsys, Atellica, and Alinity assays for measuring the anti-Hepatitis C virus (HCV) antibody

BACKGROUND

Hepatitis C virus (HCV) infection is a major cause of liver diseases in Korea. Anti-HCV assays are used to screen for HCV infection. Here, we assessed the agreement and diagnostic performances of three different anti-HCV assays.

METHODS

We analyzed 1180 samples using three assay systems-Elecsys Anti-HCV II (Roche Diagnostics), Atellica IM aHCV (Siemens Healthineers), and Alinity s Anti-HCV (Abbott Diagnostics)-and evaluated the agreements between the results and diagnostic performances.

RESULTS

The Cohens kappa coefficients between the Roche and Siemens, Siemens and Abbott, and Roche and Abbott systems were 0.837, 0.961, and 0.849, respectively. The Fleiss kappa coefficient among the three systems was 0.883. The sensitivities and positive predictive values were 86.5 and 89.8 for Roche, 97.5 and 98.1 for Siemens, and 99.4 and 98.2 for Abbott, respectively. The area under the curves of the anti-HCV signal to cutoff (S/Co) ratios or cutoff index for predicting viremia in the Roche, Siemens, and Abbott systems were 0.432, 0.641, and 0.676, respectively; the optimal S/Co ratio was 14.715 for Siemens and 14.42 for Abbott.

CONCLUSIONS

All three assays showed excellent diagnostic performance; however, anti-HCV values need to be used with caution to predict viremia; therefore, supplementary tests are necessary to confirm viremia status, especially for samples with low values.

A study based on four immunoassays: Hepatitis C virus antibody against different antigens may have unequal contributions to detection

Background

All commercial Hepatitis C virus antibody (anti-HCV) assays use a combination of recombinant antigens to detect antibody response. Antibody responses to individual antigenic regions (core, NS3/4 and NS5) used in assays have not been investigated.

Methods

In this study, we quantified HCV viral load, tested anti-HCV with four commercial assays (Ortho-ELISA, Murex-ELISA, Architect-CMIA and Elecsys-ECLIA) in 682 plasma specimens. In antigenic region ELISA platform, microwells were coated with three antigens: core (c22-3), NS3/4 (c200) and NS5 individually. The signal-to-cutoff (S/Co) values of different assays, and antibody responses to individual antigens were compared. The specimens were divided into HCV RNA positive group, anti-HCV consistent group, and anti-HCV discrepant group.

Results

Anti-core and anti-NS3/4 were simultaneously detected in 99.2% of HCV RNA positive specimens and showed great consistency with total anti-HCV signals. Responses to the core region were more robust than those to the NS3/4 region in anti-HCV consistent group (p < 0.001). Anti-NS5 only occurred in companying with responses to the core and NS3/4 antigens, and failed to affect the final anti-HCV positive signals. In anti-HCV discrepant group, 39.0% of positive signals could not be traced back to any single antigenic region.

Conclusion

Antibody responses to the core and NS3/4 antigens were stronger, whereas responses to the NS5 antigen were the weakest, indicating that individual antigenic regions played different roles in total anti-HCV signals. This study provides an impetus for optimizing commercial anti-HCV assays.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12985-021-01608-x.

Performance evaluation of immunoassay for infectious diseases on the Alinity i system

Background

Although a diagnosis of infectious diseases is essential for timely treatment, the performance of diagnostic tests has been hardly evaluated due to variable results that are influenced by multiple factors in different conditions. In the present study, the performance of the Alinity i system, which is a newly developed immunoassay to diagnose infectious diseases, was evaluated.

Methods

We evaluated the precision, linearity, correlation, and carryover of 16 analytes (HAV Ab IgG, HBsAg, HBeAg, anti‐HBc, anti‐HBe, anti‐HBs, anti‐HCV, HIV Ag/Ab, EBV VCA IgM, EBV VCA IgG, EBV EBNA IgG, CMV IgM, CMV IgG, Toxoplasma IgG, Rubella IgG, and Syphilis TP) of Alinity i by comparison with ARCHITECT i2000_SR system following the rationale of the Clinical and Laboratory Standards Institute (CLSI).

Results

For quantitative tests, the coefficients of variation (CV) % of repeatability and intermediate precision were between 0% and 4.18%. The coefficients of the linearity (r²) over a widely tested analytical range were ≥ 0.990 and the correlation between Alinity i and the ARCHITECT i2000_SR system was strong (r ≥ 0.994). For qualitative tests, the agreement between Alinity i and the ARCHITECT i2000_SR system was excellent (kappa coefficient 1) with 100% sensitivity and specificity. Carryover rates for all analytes were less than 1.0% (−0.11% ~ 0.21%).

Conclusion

The Alinity i system showed good analytical performance and favorable comparability with the ARCHITECT i2000_SR. It could be suitable as a routine immunoassay analyzer for screening and diagnosis of infectious disease.

Progress in evaluating the status of hepatitis C infection based on the functional changes of hepatic stellate cells (Review)

Hepatitis C virus (HCV) infection is a global public health problem. Cirrhosis and hepatocellular carcinoma are the main causes of death in patients with chronic hepatitis C (CHC) infection. Liver fibrosis is an important cause of cirrhosis and end‑stage liver disease after CHC infection. Along with the course of infection, liver fibrosis exhibits a progressive exacerbation. Hepatic stellate cells (HSCs) are involved in both physiological and pathological processes of the liver. During the chronic liver injury process, the activated HSCs transform into myofibroblasts, which are important cells in the development of liver fibrosis. At present, HCV infection still lacks specific markers for the accurate detection of the disease condition and progression. Therefore, the present review focused on HSCs, which are closely related to HCV‑infected liver fibrosis, and analyzed the changes in the HSCs, including their surface‑specific markers, cytokine production, activation, cell function and morphological structure. The present review aimed to propose novel diagnostic markers, at both the cellular and molecular level, which would be of great significance for the timely diagnosis of the disease. According to this aim, the characteristic changes of HSCs during HCV infection were reviewed in the present article.

Utility of grey zone testing strategy in transfusion transmissible infection testing in blood bank is of limited value!

Several blood banks use grey zone (GZ) phenomenon (defined as samples with optical density within 10% below the cut off in enzyme immuno-assay [EIA]/chemiluminescence immunoassay [CLIA]) to further augment blood safety. There is paucity of data regarding usefulness of GZ sample and its application in Transfusion Transmissible Infection (TTI) screening procedures in blood transfusion services. We looked at our GZ sample results and their confirmatory test results to verify if it adds to blood safety in our set-up? We performed a prospective analytical study on blood donors' samples over two years. All the donors' samples were screened for TTI using CLIA. Samples with signal/cut-off ratio between ≥0.90 and <1.00 were classified under GZ. They were re-tested in duplicate and submitted to confirmatory testing: Neutralization Test for HBsAg, Immunoblot for HCV, and Western blot for HIV. Among the 50,064 blood donors donating the blood during study period, 573 (1.14%) donors were reactive for HBsAg, HCV, and HIV. Forty-seven (0.1%) TTI samples were GZ, but none was "confirmed positive." The utility of GZ testing seems to be limited. However, this may be continued for sake of "erring on the side of caution" and since this only results in negligible wastage (0.1%) of blood units.

Developments in the HCV Screening Technologies Based on the Detection of Antigens and Antibodies

Hepatitis C virus (HCV) accounts for 15%-20% of cases of acute infection, and chronic HCV infection is developed in about 50%-80% of HCV patients. Unfortunately, due to the lack of proper medical care, difficulty in screening for HCV infection, and lack of awareness resulted in chronic HCV infection in 71 million people on a global scale, and about 399,000 deaths in 2016. It is crucial to recognize that the effective use of antiviral medicines can cure more than 95% of HCV infected people. The Global Health Sector Strategy (GHSS) aim is to reduce the new HCV infections and the HCV associated mortality by 90% and 65%, respectively. Therefore, the methods that are simple, yet powerful enough to detect HCV infections with high sensitivity, specificity, and a shorter window period are crucial to restrain the global burden of HCV healthcare. This article focuses on the technologies used for the detection of HCV in clinical specimens.

Chemiluminescent ELISA with multi-epitope proteins to improve the diagnosis of canine visceral leishmaniasis

Diagnosing canine visceral leishmaniasis (CVL) is difficult because clinical signs of the disease are non-specific and a many infected animals in endemic areas, as in Brazil, are asymptomatic. Serological tests are the most common diagnostic methods employed, but most have limitations. For this reason, the implementation of a rapid, sensitive, and specific diagnostic test for CVL has become increasingly important. In this study, we adapted a chemiluminescent enzyme-linked immunosorbent assay (CL ELISA), using two multi-epitope recombinant proteins (PQ10 and PQ20) and a crude Leishmania antigen produced using promastigotes of L. infantum, as antigens to detect CVL infection in animals from Belo Horizonte. To investigate cross-reactions, samples from dogs with other infections (babesiosis, ehrlichiosis and Trypanosoma cruzi) were tested. Assay performance validations were conducted to analyse parameters such as variability, reproducibility, and stability. CL ELISA sensitivity/specificity with PQ10 antigen was 93.1%/80.0%; with the PQ20 protein 93.1%/96.6%; and with the crude antigen 75%/73.3%. Inter-assay variability and inter-operator coefficient of variation were <7% and <15%, with PQ10 and PQ20, respectively. The accuracy of the CL ELISA was classified as excellent for PQ10 (AUC = 0.95) and PQ20 (AUC = 0.98) and moderate for the crude antigen (AUC = 0.77). The kappa score for qualitative agreement between two plate lots was excellent for PQ10 (0.89) and good for PQ20 (0.65). PQ20 remained more stable than PQ10. The CL ELISA with recombinant proteins is a promising tool to diagnose CVL.

Signal-to-cutoff ratios of current anti-HCV assays and a suggestion of new algorithm of supplementary testing

BACKGROUND

The detection of hepatitis C virus antibody (anti-HCV) is known to have high false-positive rates. Using signal-to-cutoff (S/Co) ratios in reflex supplemental testing, however, could reduce false-positive rates. Here, we analyzed the 2-year data of an anti-HCV assay to understand the significance of the S/Co ratio and make a new algorithm by confirming with a second anti-HCV assay.

METHODS

We reviewed 32,573 samples of the Architect assay (Abbott Diagnostics) from a tertiary hospital. Retests with the Elecsys (Roche Diagnostics) and Vitros (Ortho Clinical Diagnostics) assays were performed in 346 anti-HCV-positive samples. HCV RNA PCR and recombinant immunoblot assay (RIBA) were performed in 147 and 11 anti-HCV-positive samples, respectively.

RESULTS

Among 32,573 samples, 446 (1.37%) yielded positive results and 32,127 (98.6%) yielded negative results. Concordance rates in low S/Co samples (0.9-10.0) were 35.2%, 43.8%, and 81.9% for the Architect-Elecsys, Architect-Vitros, and Elecsys-Vitros comparisons, respectively. Correlation coefficients of S/Co ratios were as follows: Architect-Elecsys, 0.20; Architect-Vitros, 0.42; and Elecsys-Vitros, 0.46. In logistic regression, the S/Co value for predicting positivity with 95% probability was 3.13, while that for predicting 50% probability was 8.85. S/Co ratios of 1.70-3.34 showed one reactive antigen out of five antigens, and S/Co ratios of 13.54-17.72 showed three to five positive reactions out of five antigens used in the RIBA.

CONCLUSIONS

Supplementary testing of anti-HCV screening results is necessary to distinguish between true positivity and biological false positivity for anti-HCV. In this study, we presented an algorithm of supplementary testing by a retest with a second reagent, which could be useful in clinical laboratories.

Comparative evaluation of three rapid immunochromatographic test assays with chemiluminescent microparticle immunoassay for the detection of hepatitis C virus antibody

Rapid diagnostic tests (RDTs) can serve as good alternatives to standard serological assays for hepatitis C virus (HCV) detection in limited resource settings. Aim of this study was to evaluate performance of three Indian manufactured RDTs with chemiluminescent microparticle immunoassay (CLIA) for screening of HCV infection with further evaluation using HCV RNA. Serum samples tested for anti-HCV by CLIA (Architect i1000SR, Abbott Diagnostics, IL, USA) were retrieved from - 80 °C and retested for anti-HCV by three RDTs: Alere Trueline (SD Bioline; Haryana, India) (RDT 1), Benesphera HCV Rapid card test (Avantor Performance Materials India Limited; Uttarakhand, India) (RDT 2), AccuTest HCV (Accurex Biomedical Pvt. Ltd.; Mumbai, India) (RDT 3). HCV RNA results were obtained from hospital information system and anti-HCV reactive but RNA negative cases without treatment were considered as either 'false positives' or 'spontaneous clearance of HCV RNA'. Among 86 samples, 75 (87.2%), 49 (57%), 58 (67.4%) and 51 (59.3%) were reactive by CLIA, RDT1, RDT2 and RDT3, respectively. Taking CLIA as reference standard, RDT 1, 2 and 3 demonstrated sensitivity of 65.30%, 77.33% and 68% respectively. Specificity of all three RDTs was 100% with sensitivity of 97.6-100% above signal/cut-off ratio (S/Co) of 6 by CLIA and 88-100% in all HCV RNA positive cases. Sensitivity of RDTs increased from 65.30-77.33 to 72-82.4% when RNA negative/anti-HCV reactive results were considered as non-reactive. The three RDTs have acceptable sensitivity and specificity in anti-HCV detection especially in RNA positive patients that would require treatment for HCV.

Comparison of Roche Elecsys and Sysmex HISCL immunoassays for the screening of common blood-borne pathogens

Background

We conducted a comprehensive comparison in the sensitivity, specificity, dilution sensitivity, and precision between two immunoassay systems, Roche Elecsys Cobas e 601 and Sysmex HISCL 5000, for the detection of hepatitis B virus surface antigen (HBsAg), antibody to hepatitis C virus (anti-HCV), treponemal antibodies (anti-TP), and human immunodeficiency virus (HIV).

Methods

One thousand unselected samples and 100 reserved weak reactive samples were tested by the two systems. Sensitivity and specificity were then calculated for each system. Seroconversion panels were used to assess the sensitivity in early stage detection. Dilution sensitivity was evaluated by dilution tests of several seroconversion panel samples. Evaluation of within-run and intermediate precision was conducted following EP-15A protocol.

Results

The consistency rates of the two systems for the detection of four pathogens were all over 99% among unselected samples. Both Elecsys and HISCL were observed to have high sensitivity and specificity in unselected samples and weak reactive samples. Seroconversion panel tests showed that Elecsys could identify positive results earlier than HISCL in HBsAg (1 out of 4), anti-TP (1 out of 2) and HIV (1 out of 12) panels. The results of the anti-HCV panels were comparable. In dilution tests, Elecsys could detect lower concentrations than HISCL in two anti-HCV samples and one anti-TP sample. The two systems had similar performance in dilution tests of HBsAg and HIV samples. Both Elecsys and HISCL had qualified intra-assay and inter-assay precision.

Conclusions

Both Elecsys and HISCL have good performance in the screening of four common bloodborne pathogens. The two systems are comparable and considered adequate for clinical use.

Determination of parvovirus antibodies in canine serum using magnetic bead-based chemiluminescence immunoassay

Canine parvovirus type 2 (CPV-2), as a highly contagious and potentially fatal disease of dogs and many other carnivores, usually causes severe gastroenteritis and myocarditis. Therefore, it is very necessary and urgent to have an accurate method to determine the CPV-2 antibodies (CPV-2-Ab) in canine samples. Here, a magnetic bead-based chemiluminescence immunoassay was established and optimized to detect the concentration of CPV-2-Ab in serum. And a commercial assay was also used to evaluate the consistency with our method. After optimization of the detective system, the CPV-2-Ab was captured by CPV-antigen-magnetic bead (8.3 µg/mL); then combined with the conjugation of anti-canine IgG antibody-acridinium ester (0.36 µg/mL). Finally, collected the signal (read the luminosity) after 1 H reaction time. The linear correlation coefficient (R² ) is 0.9924. The limit of detection (sensitivity) is 0.36 ng/mL (the linear dynamic range: 1.32-93.75 ng/mL), and the average recovery is 100.89% without cross-reactions with other canine viral antibodies. The results' correlation between commercial assays and this method is 0.9888. This immunoassay establishes that it has high sensitivity, accuracy, and specificity in clinical analysis, indicating that this method could be suitable for quantitative detection of CPV-2-Ab and evaluation of vaccination effect.

Differential reactivity of anti-hepatitis C virus screening assays in patients with waning antibodies

Hepatitis C virus (HCV) leads to persistent infection. Viral clearance can be obtained through pharmacological treatment or spontaneously. After viral clearance, anti-HCV antibodies (Abs) slowly decline and finally disappear. Subjects with a resolved HCV infection are reactive to anti-HCV screening assays for a long time. These subjects pose a diagnostic challenge, and therefore, a more accurate interpretation of laboratory tests is needed for cases with resolved HCV infection. However, the performances of anti-HCV screening assays against declining anti-HCV Abs have not been assessed. Here we evaluated 1509 samples with different screening assays. Screening assays provided discrepant results in patients with waning Abs. The identification of signal-to-cut-off values indicative of waning Abs for each anti-HCV assay could avoid unnecessary confirmatory tests and reduce the impact of misdiagnosis.

HCV core antigen comes of age: a new opportunity for the diagnosis of hepatitis C virus infection

The diagnosis of hepatitis C virus (HCV) infection has been traditionally based on the detection of the host antibody response. Although antibody assays are available in different formats and are fairly accurate, they cannot distinguish between an ongoing infection with HCV replicative activity and a past infection where HCV has been cleared, spontaneously or after a successful therapy. As a chronic infection is mostly asymptomatic until the late clinical stages, there is a compelling need to detect active HCV infection by simple and reproducible methods. On this purpose, the clinical guidelines have suggested to search for the HCV ribonucleic acid (HCV-RNA) after anti-HCV has been detected, but this second step carries several limitations especially for population screening. The availability of fast and automated serological assays for the hepatitis C core antigen (HCVAg) has prompted an update of the guidelines that now encompass the use of HCVAg as a practical alternative to HCV-RNA, both for screening and monitoring purposes. In this paper, we summarize the features, benefits and limitations of HCVAg testing and provide an updated compendium of the evidences on its clinical utility and on the indications for use.

Comparative Analysis of Electrochemiluminescence Assay and Chemiluminescent Microparticle Immunoassay for the Screening of Hepatitis C

The primary objective of the study was to identify a highly sensitive and specific screening technique for the detection of Hepatitis C infection in healthy blood donors in a low prevalence area for HCV. In this study, two of the most commonly used methods for Anti-HCV screening, i.e., Electrochemiluminescence Immunoassay (ECLIA) and Chemiluminescent Microparticle Immunoassay (CMIA) were performed among 517 selected healthy blood donors. The clinical performance of ECLIA and CMIA was compared on the basis of their operational variables, i.e., Sensitivity, Specificity, Accuracy, Youden's J index, Positive and Negative predictive values and False discovery, False positive and False negative rate, etc., Both ECLIA and CMIA are highly sensitive (100%) and specific (98%) in terms of anti HCV detection among the blood donors. According to the clinical performance of ECLIA and CMIA, both are efficient in detecting anti-HCV antibodies among the asymptomatic population of healthy blood donors. But as both of them are associated with false positive results, it is recommended to have Polymerase chain reaction on the reactive samples to detect the HCV RNA.

Development of a Rapid Automated Fluorescent Lateral Flow Immunoassay to Detect Hepatitis B Surface Antigen (HBsAg), Antibody to HBsAg, and Antibody to Hepatitis C

Background

Accurate, rapid, and cost-effective screening tests for hepatitis B virus (HBV) and hepatitis C virus (HCV) infection may be useful in laboratories that cannot afford automated chemiluminescent immunoassays (CLIAs). We evaluated the diagnostic performance of a novel rapid automated fluorescent lateral flow immunoassay (LFIA).

Methods

A fluorescent LFIA using a small bench-top fluorescence reader, Automated Fluorescent Immunoassay System (AFIAS; Boditech Med Inc., Chuncheon, Korea), was developed for qualitative detection of hepatitis B surface antigen (HBsAg), antibody to HBsAg (anti-HBs), and antibody to HCV (anti-HCV) within 20 minutes. We compared the diagnostic performance of AFIAS with that of automated CLIAs—Elecsys (Roche Diagnostics GmbH, Penzberg, Germany) and ARCHITECT (Abbott Laboratories, Abbott Park, IL, USA)—using 20 seroconversion panels and 3,500 clinical serum samples.

Results

Evaluation with the seroconversion panels demonstrated that AFIAS had adequate sensitivity for HBsAg and anti-HCV detection. From the clinical samples, AFIAS sensitivity and specificity were 99.8% and 99.3% for the HBsAg test, 100.0% and 100.0% for the anti-HBs test, and 98.8% and 99.1% for the anti-HCV test, respectively. Its agreement rates with the Elecsys HBsAg, anti-HBs, and anti-HCV detection assays were 99.4%, 100.0%, and 99.0%, respectively. AFIAS detected all samples with HBsAg genotypes A-F and H and anti-HCV genotypes 1, 1a, 1b, 2a, 2b, 4, and 6. Cross-reactivity with other infections was not observed.

Conclusions

The AFIAS HBsAg, anti-HBs, and anti-HCV tests demonstrated diagnostic performance equivalent to current automated CLIAs. AFIAS could be used for a large-scale HBV or HCV screening in low-resource laboratories or low-to middle-income areas.

Performance evaluation of the mindray anti-HCV assay for the detection of hepatitis C virus infection

BACKGROUND

Anti-hepatitis C virus (anti-HCV) antibody assays are recommended for HCV infection screening. The Mindray anti-HCV assay, based on a third-generation immunoassay, was recently launched in China. We aimed to evaluate its diagnostic performance compared with that of two other widely used assays.

METHODS

Six HCV infection seroconversion panels were used to evaluate the sensitivity of the assay for early detection. A total of 1952 clinical samples were tested by the Mindray anti-HCV, Elecsys anti-HCV II, and Architect anti-HCV assays. Samples with reactive results using at least one anti-HCV assay were further tested with the recombinant immunoblot assay (RIBA). Inconsistent results were investigated by the HCV RNA assay and HCV core antigen assay. HCV infection diagnosis was made according to the results of laboratory tests and medical records.

RESULTS

The Mindray anti-HCV assay and Elecsys anti-HCV II assay detected seroconversion in an average of 12.5 days and 10.5 days, respectively, and this difference was not significant (P = .818). Of the 1952 cases, 90 were categorized as "HCV infection" and 1862 were categorized as "no HCV infection." The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (LR+), and negative likelihood ratio (LR-) of each assay were as follows: the Mindray anti-HCV assay, 95.6%, 99.2%, 85.1%, 99.8%, 118.6 and 0.045, respectively; the Architect anti-HCV assay, 98.9%, 95.2%, 50.0%, 99.9%, 20.69 and 0.012, respectively; and the Elecsys anti-HCV II assay, 96.7%, 99.9%, 98.9%, 99.8%, 1799.9 and 0.033, respectively. There were significant differences in the specificity, PPV and LR+ among the three assays (P < .001). There were no significant differences in the sensitivity, NPV or LR- among the three assays (P > .05).

CONCLUSIONS

The Mindray anti-HCV assay displays a similar sensitivity to the Elecsys anti-HCV II assay with respect to the early detection of HCV infection. The Mindray anti-HCV assay shows excellent diagnostic performance and is suitable for the screening of HCV infection.

Comparison of 2 different antibody assay methods, Elecsys Anti-HCVII (Roche) and Vidas Anti-HCV (Biomerieux), for the detection of antibody to hepatitis C virus in Egypt

The measurement of antibodies against hepatitis C virus (HCV) is important to screen HCV infection. The aim of this study is to investigate the reliability of 2 commercially available anti-HCV antibody kits used in routine laboratory testing in Egypt. One thousand nine hundred and thirty-one serum samples were analyzed using 2 anti-HCV test systems: Cobas e 411® Elecsys Anti-HCVII and Vidas® Anti-HCV Biomerieux. Discrepant samples were tested using the recombinant immunoblot assay Innogenetics® INNO-LIA HCV Score. Overall agreement of the 2 tests was 94%. Following discrepant sample testing by LIA, sensitivity and specificity using Vidas were 94% and 99%, respectively, while those for Cobas were 97% and 96%, respectively. This study demonstrates superior specificity by Vidas and higher sensitivity by Cobas. Both methods are suitable for laboratory and/or blood screening programs. The concomitant use of a supplementary or confirmatory assay is necessary to compare the accuracy of HCV serological assays.

Diagnostic reliability of Architect anti-HCV assay: Experience of a tertiary care hospital in India

BACKGROUND & AIMS

Anti-HCV assays are prone to false positive results. Thus, accurate detection of HCV infection is critical for the timely therapeutic management. This study ascertained the reliability of Architect anti-HCV assay (Abbott) and to estimate the agreement of this assay with Ortho HCV 3.0 ELISA Test System with Enhanced SAVe (Ortho), HCV Tri-dot (Tri-dot) and HCV-PCR in a tertiary care setting.

METHODS

A total of 78 788 consecutive sera were routinely screened for anti-HCV antibodies using Architect. All repeatedly reactive anti-HCV sera (n=1000) and anti-HCV negative sera (n=300) were tested in Ortho and in Tri-dot assays. Representative proportions of sera (n=500) with various signal-to-cut-off (S/Co) ratio were also compared with HCV-PCR.

RESULTS

When Architect was compared with Ortho, Tri-dot, and HCV-PCR, the level of agreement as assessed by kappa were .26, .16, and .27 respectively. Using Latent class analysis (LCA), we found that sensitivity and specificity were 100% and 36.1% for Architect, 93.8% and 100% for Ortho and 63.8% and 100% for Tri-dot respectively. The median S/CO ratio of Architect and Ortho anti-HCV assays were significantly different between HCV-PCR positive and negative results (P<.0001). Furthermore, Architect S/CO ratio of >8 showed higher accuracy indices in both anti-HCV assays.

CONCLUSIONS

Architect can be used as a screening assay because of its high sensitivity, high throughput, and short turnaround time. However, S/Co ratios of ≥1 to <8 in Architect necessitates HCV PCR to identify current infection and or EIA to distinguish true positivity from false biological positivity.

Retrospective analysis on the diagnostic performances and signal-to-cut-off ratios of the Elecsys Anti-HCV II assay

BACKGROUND

Anti-HCV assays are widely used as a screening tool for HCV infection. However, diagnostic performances and effective signal-to-cut-off ratios (S/COs) for predicting true HCV infections would vary according to the assays used. Thus, we evaluated the diagnostic performances of the new Elecsys Anti-HCV assay.

METHODS

A total of 41 694 cases tested by the Elecsys Anti-HCV II assay (Roche Diagnostics, Germany) during January 2013 to December 2015 were retrospectively analyzed by comparing with the diagnosis on HCV infections determined by patients' medical records and results of laboratory tests.

RESULTS

Excluding 62 cases with unclear history of HCV infection, 430 and 41 202 cases were respectively assorted as "true infection" and "no evidence of infection," and 99.85% of the initial results by the Elecsys assay were concordant with the diagnosis on HCV infection. Sensitivity, specificity, positive and negative predictive values were respectively 99.30%, 99.86%, 88.04%, and 99.99%, where the prevalence of the HCV infection was 1.0%. The area under the receiver operating characteristics curve value of the Elecsys assay was 0.9980 (95% confidence interval [CI]=0.9944 to 1.0017). The S/CO by the Elecsys assay for predictive of a true-positive ≥95% of the time was 19.0 (95% CI=15.0 to 25.1).

CONCLUSION

The Elecsys Anti-HCV II assay showed excellent diagnostic performances, particularly in terms of sensitivity, specificity, and NPV. However, the results obtained by this assay with S/CO less than a certain value would need to be retested by HCV RNA PCR or another anti-HCV assay.

Evaluation of the VIDAS Anti-HCV Assay for Detection of Hepatitis C Virus Infection

BACKGROUND

Anti-hepatitis C virus antibody (anti-HCV) assays are recommended for screening HCV-infected persons. The VIDAS Anti-HCV Assay (bioMérieux, France), based on the enzyme-linked fluorescence test principle, was recently introduced in Korea. We evaluated the clinical performance of the VIDAS assay.

METHODS

One hundred HCV-positive and 1,002 HCV-negative blood samples confirmed by Architect anti-HCV (Abbott Laboratories, USA) and COBAS TaqMan HCV real-time PCR (Roche Diagnostics, USA) or the Procleix Ultrio Plus Assay (Gen-Probe Incorporated, USA) were obtained from the Human Serum Bank (HSB) and tested by VIDAS. In case of discrepant results, we conducted a recombinant immunoblot assay (RIBA).

RESULTS

The agreement rates for known HCV-positive and HCV-negative samples between the VIDAS assay and the HSB testing were 100% (95% confidence interval [CI]: 96.4-100%) and 99.5% (95% CI: 98.8-99.8%), respectively. One of the five discrepant samples was positive for Core 2+ and NS3-2 2+ reactivity, two samples were negative, and the other two were indeterminate regarding NS4 2+ reactivity in RIBA. We observed a significant but weak positive correlation between the titers of VIDAS and Architect assays (r=0.315, P<0.001).

CONCLUSIONS

The VIDAS anti-HCV assay, developed on the VIDAS automated immunoassay platform based on the ready-to-use, single-sample test concept may be useful in small-to-medium-sized laboratories. It showed good agreement with Architect anti-HCV and COBAS PCR assays and is therefore useful for detection of HCV infection. Weakly test-positive (ambiguous) samples require additional testing by another anti-HCV, RIBA, or HCV RNA assay.

Screening for Human Immunodeficiency Virus, Hepatitis B Virus, Hepatitis C Virus, and Treponema pallidum by Blood Testing Using a Bio-Flash Technology-Based Algorithm before Gastrointestinal Endoscopy

Currently, conventional enzyme immunoassays which use manual gold immunoassays and colloidal tests (GICTs) are used as screening tools to detect Treponema pallidum (syphilis), hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus type 1 (HIV-1), and HIV-2 in patients undergoing surgery. The present observational, cross-sectional study compared the sensitivity, specificity, and work flow characteristics of the conventional algorithm with manual GICTs with those of a newly proposed algorithm that uses the automated Bio-Flash technology as a screening tool in patients undergoing gastrointestinal (GI) endoscopy. A total of 956 patients were examined for the presence of serological markers of infection with HIV-1/2, HCV, HBV, and T. pallidum The proposed algorithm with the Bio-Flash technology was superior for the detection of all markers (100.0% sensitivity and specificity for detection of anti-HIV and anti-HCV antibodies, HBV surface antigen [HBsAg], and T. pallidum) compared with the conventional algorithm based on the manual method (80.0% sensitivity and 98.6% specificity for the detection of anti-HIV, 75.0% sensitivity for the detection of anti-HCV, 94.7% sensitivity for the detection of HBsAg, and 100% specificity for the detection of anti-HCV and HBsAg) in these patients. The automated Bio-Flash technology-based screening algorithm also reduced the operation time by 85.0% (205 min) per day, saving up to 24 h/week. In conclusion, the use of the newly proposed screening algorithm based on the automated Bio-Flash technology can provide an advantage over the use of conventional algorithms based on manual methods for screening for HIV, HBV, HCV, and syphilis before GI endoscopy.

Evaluation of the Novel HISCL Chemiluminescence Enzyme Immunoassay for Laboratory Screening of Hepatitis C Virus

The hepatitis C virus (HCV) antibody assay remains the first-line screening test to identify HCV infection. The newly arrived HISCL Anti-HCV assay had a satisfactory seroconversion sensitivity. Its sensitivity and specificity were 98.97 and 100% for clinical samples. In general, the HISCL Anti-HCV assay may be a novel choice for clinical HCV screening.

Multicenter clinical evaluation of the new 3rd generation assay for detection of antibodies against hepatitis C virus on the VIDAS(®) system

BACKGROUND

Detection of antibodies (anti-HCV) against hepatitis C virus (HCV) is indispensable for screening and diagnosis of viral hepatitis and for the viral safety of blood, tissue or organ donations. It gains additional importance by the new HCV drugs which improve the therapeutic possibilities dramatically.

OBJECTIVE

To evaluate the performance of a newly developed immune assay for anti-HCV based on the well-established VIDAS platform.

STUDY DESIGN

The assay was evaluated with samples from anti-HCV negative blood donors and from patients with or without HCV markers in six centres in France, Spain and Egypt. The status of the samples was determined by using CE-marked immune assays (Architect, AxSym, Prism, Vitros), two immunoblots (RIBA, Inno-Lia) and/or HCV RNA results.

RESULTS

Specificity was 99.67% in 10,320 French blood donors without anti-HCV, 99.5% in 200 anti-HCV negative hospitalized European patients and 99.0% in 198 negative patients from Egypt. Sensitivity was 99.7% in 1054 patients pretested positive by other assays; 345 patients with known genotype had genotype 1-6; 61 patients were co-infected with HIV. VIDAS was reactive in 78% of 91 patients with uncertain or very weak anti-HCV. It became on average positive at day 37 with seroconversion panels.

CONCLUSIONS

This multicentric, international study with >12,000 samples show that the new VIDAS anti-HCV assay is very suitable for screening and confirmation of HCV infection. Sensitivity, specificity and recognition of seroconversion compare favorably with well-established CE-marked tests and help to clarify discrepant results obtained with other assays.

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.

Biomarkers in HCV Infection

Liver-related biomarkers have been developed and validated mainly in patients with chronic hepatitis C for the prediction of liver fibrosis or cirrhosis, which is a final pathway of chronic liver injury. They are noninvasive, traceable, and easy-to-use. Biomarkers provide implications related to screening, diagnosis, treatment, and prognosis of chronic hepatitis. For the improvement of performance and coverage, biomarker panels, imaging biomarkers, and even genetic biomarkers have been developed. With the advancement of genomics and proteomics, earlier and more precise prediction is expected in the near future. In this review, multiple biomarker panels for the estimation of the degree of fibrosis in chronic hepatitis C, biomarkers for the screening and diagnosis of hepatitis C, biomarkers for the treatment of hepatitis C, biomarkers for the prediction of complications related to the chronic hepatitis C, and future perspectives will be summarized.

Diagnosis and Management of Hepatitis C Virus Infection

The hepatitis C virus (HCV) infects more than 200 million people globally, with increasing incidence, especially in developing countries. HCV infection frequently progresses to chronic liver disease, creating a heavy economic burden on resource-poor countries and lowering patient quality of life. Effective HCV diagnosis, treatment selection, and treatment monitoring are important in stopping disease progression. Serological assays, which detect anti-HCV antibodies in the patient after seroconversion, are used for initial HCV diagnosis. Qualitative and quantitative molecular assays are used to confirm initial diagnosis, determine viral load, and genotype the dominant strain. Viral load and genotype information are used to guide appropriate treatment. Various other biomarker assays are performed to assess liver function and enable disease staging. Most of these diagnostic methods are mature and routinely used in high-resource countries with well-developed laboratory infrastructure. Few technologies, however, are available that address the needs of low-resource areas with high HCV prevalence, such as Africa and Southeast Asia.

Evaluation of the Elecsys(®) Anti-HCV II assay for routine hepatitis C virus screening of different Asian Pacific populations and detection of early infection

BACKGROUND

Early diagnosis of hepatitis C virus (HCV) infection is essential to allow appropriate treatment and prevent transmission.

OBJECTIVES

To evaluate the Elecsys(®) Anti-HCV II assay as a routine screening assay in Asia using a large number of samples from different Asian Pacific populations and compare its performance with other HCV assays routinely used in the region.

STUDY DESIGN

The sensitivity and specificity of the Elecsys(®) Anti-HCV II assay were determined using routine hospital samples and compared with at least one of the following comparator assays at nine independent centers: ARCHITECT™ Anti-HCV; Serodia(®)-HCV Particle Agglutination; Vitros(®) ECi Anti-HCV; Elecsys(®) Anti-HCV; ADVIA Centaur(®) HCV; InTec(®) HCV EIA; or Livzon(®) Anti-HCV. Commercially available seroconversion panels were used to assess sensitivity for early detection of infection.

RESULTS

The Elecsys(®) Anti-HCV II assay was more sensitive in recognizing early infection and detected acute HCV infection earlier on average than the comparator assays for all six panels tested. 7,726 routine samples were tested and 322 identified as HCV positive. Elecsys(®) Anti-HCV II had a sensitivity of 100% and a specificity of 99.66%, both of which were comparable or superior to the results obtained for competitor assays, which ranged from 87.5-100% and 98.98-100%, respectively.

CONCLUSIONS

The Elecsys(®) Anti-HCV II assay has the sensitivity and specificity to support its use as a routine screening method in the Asia Pacific region. Furthermore, this assay shortens the diagnostic window between infection and the detection of antibodies compared with established methods.

Analytical model for calculating indeterminate results interval of screening tests, the effect on seroconversion window period: a brief evaluation of the impact of uncertain results on the blood establishment budget

The evaluation of measurement uncertainty is not required by the European Union regulation or blood establishments’ laboratory tests. However, it is required for tests accredited by ISO 15189. Also, the forthcoming ISO 9001 edition requires “risk based thinking” with risk described as “the effect of uncertainty on an expected result”. ISO recommends GUM models for determination of measurement uncertainty, but their application is not intended for ordinal value measurements, such as what happens with screening test binary results. This article reviews, discusses and proposes concepts intended for measurement uncertainty of screening test results. The precision model focuses on cutoff level allowing the evaluation of the indeterminate interval using analytical sources of variance. The intervalis considered in the estimation of the seroconversion window period. The delta-value of patients and healthy subjects’ samples allows ranking two tests according to the probability of the two classes of indeterminate results: chance of false negative results and chance of false positive results (waste on budget).

Screening tests for hepatitis B virus, hepatitis C virus, and human immunodeficiency virus in blood donors: evaluation of two chemiluminescent immunoassay systems

Automated chemiluminescent immunoassays (CLIAs) are useful for the detection of hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus 1/2 antigen/antibodies (HIV 1/2 Ag/Ab) in blood donor screening. Eight hundred and forty serum samples were tested for hepatitis B surface antigen (HBsAg), HCV antibodies (anti-HCV), and HIV1/2 Ag/Ab in parallel using 2 different CLIAs (Abbott Architect i2000SR and Roche Cobas e411). The concordance between the 2 systems was high (Cohen's kappa 0.97 for HBsAg, 0.77 for anti-HCV, 0.92 for HIV1/2 Ag/Ab) and the specificity and the positive predictive value were comparable. Among the 12 discrepant results, 11 were false-positive and 1 (reactive by Architect) was true-positive for anti-HCV. Positivity for HBV DNA, HCV RNA, and HIV RNA was recorded in 90.9%, 38.9%, and 100% of true-positive samples, respectively. This study represents the first stringent comparison between Architect i2000SR and Cobas e411 in blood donors. We observed a good correlation and high agreement among HBV, HCV, and HIV with the 2 automated systems.

Hepatitis C virus: Screening, diagnosis, and interpretation of laboratory assays

An estimated 3% of the world population is infected with Hepatitis C virus (HCV), a hepatotropic RNA virus, transmitted primarily via the blood route. The major modes of transmission of the virus include injection drug use, unsafe injection practices, blood transfusion etc. HCV causes chronic hepatitis in about 80% of those infected by it. The mainstay in diagnosing infection with HCV is to initially screen high risk groups for antibodies to HCV (anti-HCV). The inclusion of serum to cut-off ratio (S/CO) in recent guidelines is helpful in deciding the supplemental assay to be used to confirm initially reactive screening results. Nucleic acid amplification tests (NAT) are used as confirmatory tools, and also to determine viral load prior to initiating treatment. Quantitative NAT has replaced qualitative assays. Genotyping is an important tool in clinical management to predict the likelihood of response and determine the optimal duration of therapy. The impact of this infection has begun to emerge in India. The problem of professional blood donation despite an existing law against it, and flourishing unsafe injection practices, are potential sources for the spread of hepatitis C in our country. All health care practitioners need to understand how to establish or exclude a diagnosis of HCV infection and to interpret the tests correctly. In the absence of a preventive or therapeutic vaccine, and also of post-exposure prophylaxis against the virus, it is imperative to diagnose infection by HCV so as to prevent hepatic insult and the ensuing complications that follow, including primary hepatocellular carcinoma (HCC). This review aims to help blood bank staff regarding options for diagnosis and management of donors positive for HCV.

Indeterminate RIBA results were associated with the absence of hepatitis C virus RNA (HCV-RNA) in blood donors

INTRODUCTION

Hepatitis C virus (HCV) infection is diagnosed by the presence of antibodies and is supplemented by confirmatory testing methods, such as recombinant immunoblot assay (RIBA) and HCV-RNA detection. This study aimed to evaluate the efficacy of RIBA testing to diagnose HCV infection in blood donors positive for anti-HCV antibodies.

METHODS

A total of 102 subjects positive for anti-HCV determined by enzyme-linked immunosorbent assay (ELISA) at the Hematology and Hemotherapy Foundation of Bahia (HEMOBA) were later assessed with new samples using the Abbott Architect anti-HCV test (Abbott Diagnostics, Wiesbaden, Germany), the RIBA III test (Chiron RIBA HCV 3.0 SIA, Chiron Corp., Emeryville, CA, USA), the polymerase chain reaction (PCR; COBAS® AMPLICOR HCV Roche Diagnostics Corp., Indianapolis, IN, USA) and line probe assay (LiPA - Siemens, Tarrytown, NY, USA) genotyping for HCV diagnosis.

RESULTS

Of these new samples, 38.2% (39/102) were positive, 57.8% (59/102) were negative and 3.9% (4/102) were indeterminate for anti-HCV; HCV-RNA was detected in 22.5% (23/102) of the samples. RIBA results were positive in 58.1% (25/43), negative in 9.3% (4/43) and indeterminate in 32.6% (14/43) of the samples. The prevailing genotypes were 1 (78.3%, 18/23), 3 (17.4%, 4/23) and 2 (4.3%, 1/23). All 14 samples with indeterminate RIBA results had undetectable viral loads (detection limit ≤50 IU/mL). Of these samples, 71.4% (10/14) were reevaluated six months later. Eighty percent (8/10) of these samples remained indeterminate by RIBA, and 20% (2/10) were negative.

CONCLUSIONS

In this study, individuals with indeterminate RIBA results had no detectable HCV-RNA.

Comparison between screening and confirmatory serological assays in blood donors in a region of South Italy

BACKGROUND

Screening assays are needed in order to guarantee safety of donated blood, but a significant number of safe donations are removed from blood supply because of reactive screening results. It is important to evaluate the positive predictive value (PPV) of screening assays in order to modulate confirmatory algorithm and implement an adequate counseling.

METHODS

An analysis of 17,912 blood donations has been conducted at Transfusion Medicine at Second University Naples, Italy, in 2009-2012. Serological screening for syphilis, hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) was performed by ARCHITECT (Abbott Diagnostics, Wiesbaden, Germany); repeatedly reactive (RR) samples were checked by respective confirmatory tests. The relationship between sample/cutoff and confirmed seropositivity were analyzed.

RESULTS

RR rates were low as expected in blood donors: 0.47% for syphilis, 0.42% for HBV, 0.50% for HCV, and 0.15% for HIV. The specificity on RR + gray zone (GZ) was 99.67%, 99.79%, 99.77%, and 99.88%, respectively; due to the low prevalence, PPV value was 30.6% for syphilis, 50.7% for HBV, 42.2% for HCV, and 18.5% for HIV. These values increased substantially reaching a plateau of 89.3% for syphilis, 94.6% for HBV, 85.7% for HCV, and 100% for HIV at the threshold established by receiver operating characteristics curve analysis.

CONCLUSIONS

Supplemental testing on samples with high signal by screening assays seems to add little information. GZ settings and confirmatory testing for positive screening results should be designed taking in account several factors, including difference in the natural history among blood-borne infections, the characteristics of first- and second-level tests, and, when available, the results of nucleic acid amplification testing.

Laboratory diagnosis of viral infection

Since the last Handbook of Clinical Neurology volume on this topic, viral diagnosis has made tremendous strides, moving from the margin to the mainstream of clinical care. For many years, conventional virus isolation was the mainstay of viral diagnosis since it was sensitive and “open-minded.” However, growth in conventional cell culture entails an inherent delay that limits its clinical impact. Although rapid culture and viral antigen methods detect fewer pathogens and are less sensitive than conventional culture, both require less expertise and have greatly reduced time to result. Polymerase chain reaction has ushered in a new era in virology, especially in the diagnosis of neurologic diseases. Molecular amplification methods are rapid, highly sensitive, can be automated, quantitative, and detect viruses not amenable to routine culture. User-friendly, walk-away tests with results in an hour, as well as multiplex tests that can detect 20 viruses in a single reaction, are now a reality. As the variety of test methods and commercial products proliferate, the challenges for clinicians and laboratories are selecting which tests to utilize in which clinical scenarios, and understanding how to interpret the results. The advantages and limitations of each method are discussed in this chapter, with special attention to neurologic disease.

Clinical performance of the novel DiaSorin LIAISON(®) XL murex: HBsAg Quant, HCV-Ab, HIV-Ab/Ag assays

BACKGROUND

The fully automated and closed LIAISON(®)XL platform was developed for reliable detection of infection markers like hepatitis B virus (HBV) surface antigen (HBsAg), hepatitis C virus (HCV) antibodies (Ab) or human immunodeficiency virus (HIV)-Ag/Ab. To date, less is known about the diagnostic performance of this system in direct comparison to the common Abbott ARCHITECT(®) platform.

OBJECTIVES

We compared the diagnostic performance and usability of the DiaSorin LIAISON(®)XL with the commonly used Abbott ARCHITECT(®) system.

STUDY DESIGN

The qualitative performance of the above mentioned assays was compared in about 500 sera. Quantitative tests were performed for HBsAg-positive samples from patients under therapy (n=289) and in vitro expressed mutants (n=37). For HCV-Ab, a total number of 155 selected samples from patients chronically infected with different HCV genotypes were tested.

RESULTS

The concordance between both systems was 99.4% for HBsAg, 98.81% for HCV-Ab, and 99.6% for HIV-Ab/Ag. The quantitative LIAISON(®)XL murex HBsAg assay detected all mutants in comparable amounts to the HBsAg wild type and yielded highly reliable HBsAg kinetics in patients treated with antiviral drugs. Dilution experiments using the 2nd International Standard for HBsAg (WHO) showed a high accuracy of this test. HCV-Ab from patients infected with genotypes 1-3 were equally detected in both systems. Interestingly, S/CO levels of HCV-Ab from patients infected with genotype 3 seem to be relatively low using both systems.

CONCLUSIONS

The LIAISON(®)XL platform proved to be an excellent system for diagnostics of HBV, HCV, and HIV with equal performance compared to the ARCHITECT(®) system.

Detection limit of architect hepatitis C core antigen assay in correlation with HCV RNA, and renewed confirmation algorithm for reactive anti-HCV samples

BACKGROUND

hepatitis C infections are detected by anti-HCV screening tests. Reactive anti-HCV results give no information about the presence or absence of hepatitis C viruses, or of unspecific reactivity. To obtain information about the viral load, HCV RNA measurements, following a reactive anti-HCV result, are performed in well equipped and specialised laboratories. Anti-HCV immunoblots are the only means to exclude non specific reactivity. The measurement of HCV core antigen (HCV-Ag), as an alternative to HCV RNA, is discussed, as it can be analysed on the same instrument as anti-HCV.

OBJECTIVES

The detection limit of HCV-Ag is crucial to use it in lieu of HCV RNA, in regard of the different genotypes. A renewed algorithm is proposed to exclude unspecific reactivity of anti-HCV.

STUDY DESIGNS

Samples were tested on Architect i2000SR (Abbott) for anti-HCV and HCV-Ag. HCV RNA measurements were obtained by Cobas Ampliprep/Taqman (Roche) or m2000rt(®) (Abbott).

RESULTS AND CONCLUSIONS

Comparison between HCV-Ag and HCV RNA from 126 samples of 101 patients with chronic hepatitis C gave linear regression R(2) 0.89, slope 0.885 and intercept -2.258, which were independent of the genotypes. The detection limit of HCV-Ag was between 2.4 and 4.5 Log(10)IU/mL. A renewed algorithm for confirmation of reactive anti-HCV results is proposed: active or resolved hepatitis C infections or false reactivity can be differentiated by sequenced reflex testing due to HCV-Ag, anti-HCV immunoblot and HCV RNA.

Performance evaluation of a new fourth-generation HIV Ag/Ab combination electrochemiluminescence immunoassay – evaluation of a new HIV assay

A new fourth-generation HIV Ag/Ab electrochemiluminescence immunoassay for screening of HIV infection, the Elecsys® HIV Combi PT (Roche Diagnostics, Penzberg, Germany) assay, is going to be commercially available in clinical laboratories in China. This assay was evaluated and compared with two commonly used assays: Elecsys® HIV Combi assay and the Livzon anti-HIV-1/2 ELISA. Commercially available panels and 30 established HIV infection samples were tested to evaluate the sensitivity. In addition, a total of 675 routine clinical samples were collected and tested in West China Hospital to compare the specificity. Any reactive result from a screening test was retested and all reactive retested samples were confirmed with Western blot assay, Elecsys® HIV Ag test, Elecsys® HIV Ag confirmatory test or HIV-1 RNA NAT testing. According to the results of the HIV seroconversion panels, the Elecsys® HIV Combi PT could detect seroconversion at the same bleed or at least one bleed earlier compared to the other two assays. Among the 675 clinical samples, most results were consistent except for one specimen with a false-negative result using Elecsys® HIV Combi assay. In conclusion, the Elecsys® HIV Combi PT has shown satisfactory sensitivity and specificity to be a screening test for HIV infection.

Evaluation of a rapid on-site anti-HCV test as a screening tool for hepatitis C virus infection

BACKGROUND

In settings such as needle-stick injuries or intravenous drug abuse, immediate knowledge of the anti-hepatitis C virus (HCV) serostatus instead of waiting for the results of a laboratory-based test can be important to guide further medical procedures and appropriate hygienic advises. Thus, a rapid on-site anti-HCV test was evaluated in daily clinical routine and compared with a laboratory-based certified assay.

PATIENTS AND METHODS

Ten microliters of serum or EDTA whole blood was analyzed using a chromatographic immunoassay (Toyo anti-HCV test). Results were available on-site 5-15 min after sample centrifugation. The Architect anti-HCV test served as a reference method.

RESULTS

Sera of 189 patients were analyzed (without HCV infection: n=105; HCV infection: n=84). The assay was evaluable in 185 cases (98%). The sensitivity and specificity were 99 and 88%, respectively. With EDTA whole blood, the test was evaluable in 47/52 samples (90%). Forty-six of 47 evaluable EDTA tests were concordant with serum results. The one HCV patient with an unevaluable serum test was diagnosed correctly with the EDTA sample.

CONCLUSION

The rapid chromatographic anti-HCV immunoassay has limited specificity, which impairs clinical practicability. A positive result warrants re-evaluation with a certified serologic assay.

Detection of infections with hepatitis B virus, hepatitis C virus, and human immunodeficiency virus by analyses of dried blood spots--performance characteristics of the ARCHITECT system and two commercial assays for nucleic acid amplification

BACKGROUND

Nowadays, dried blood spots (DBS) are primarily used to obtain diagnostic access to risk collectives such as intravenous drug users, who are prone to infections with hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV). Before DBS analyses can be used in this diagnostic context, however, a comprehensive evaluation of its performance characteristics must be conducted. To the best of our knowledge, the current study presents for the first time such essential data for the Abbott ARCHITECT system, which is currently the worldwide leading platform in this field of infection diagnostics.

METHODS

The investigation comprised 1,762 paired serum/DBS samples and a total of 3,524 determinations with the Abbott ARCHITECT HBsAg, anti-HBc, anti-HBs, anti-HCV and HIV-1-p24-antigen/anti-HIV 1/2 assays as well as with the artus HBV LC PCR and VERSANT HCV RNA qualitative (TMA) tests.

RESULTS

In the context of DBS testing, a specificity of 100% was recorded for the seven serological and molecular biological assays. The analytical sensitivity of HBsAg, anti-HBc, anti-HBs, anti-HCV, HIV-1-p24-antigen/anti-HIV 1/2, HBV DNA, and HCV RNA detections in DBS eluates was 98.6%, 97.1%, 97.5%, 97.8%, 100%, 93%, and 100%, respectively.

DISCUSSION/CONCLUSIONS

The results obtained indicate that it is today possible to reliably detect HBsAg, anti-HBc, anti-HBs, anti-HCV and HIV-1-p24 antigen/anti-HIV 1/2 with state-of-the-art analytical systems such as the Abbott ARCHITECT in DBS eluates even when a comparatively high elution volume of 1,000 μl is used. They also provide evidence for the inherent analytical limits of DBS testing, which primarily concern the anti-HBc/anti-HBs system for individuals with HIV infections and nucleic acid tests with relatively low analytical sensitivity.

Detection of infections with hepatitis B virus, hepatitis C virus, and human immunodeficiency virus by analyses of dried blood spots--performance characteristics of the ARCHITECT system and two commercial assays for nucleic acid amplification

BACKGROUND

Nowadays, dried blood spots (DBS) are primarily used to obtain diagnostic access to risk collectives such as intravenous drug users, who are prone to infections with hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV). Before DBS analyses can be used in this diagnostic context, however, a comprehensive evaluation of its performance characteristics must be conducted. To the best of our knowledge, the current study presents for the first time such essential data for the Abbott ARCHITECT system, which is currently the worldwide leading platform in this field of infection diagnostics.

METHODS

The investigation comprised 1,762 paired serum/DBS samples and a total of 3,524 determinations with the Abbott ARCHITECT HBsAg, anti-HBc, anti-HBs, anti-HCV and HIV-1-p24-antigen/anti-HIV 1/2 assays as well as with the artus HBV LC PCR and VERSANT HCV RNA qualitative (TMA) tests.

RESULTS

In the context of DBS testing, a specificity of 100% was recorded for the seven serological and molecular biological assays. The analytical sensitivity of HBsAg, anti-HBc, anti-HBs, anti-HCV, HIV-1-p24-antigen/anti-HIV 1/2, HBV DNA, and HCV RNA detections in DBS eluates was 98.6%, 97.1%, 97.5%, 97.8%, 100%, 93%, and 100%, respectively.

DISCUSSION/CONCLUSIONS

The results obtained indicate that it is today possible to reliably detect HBsAg, anti-HBc, anti-HBs, anti-HCV and HIV-1-p24 antigen/anti-HIV 1/2 with state-of-the-art analytical systems such as the Abbott ARCHITECT in DBS eluates even when a comparatively high elution volume of 1,000 μl is used. They also provide evidence for the inherent analytical limits of DBS testing, which primarily concern the anti-HBc/anti-HBs system for individuals with HIV infections and nucleic acid tests with relatively low analytical sensitivity.