Evaluation of newly developed microparticle enzyme immunoassays for the detection of HCV antibodies

[Evaluation of HBs Ag, HCV and HIV Ag-Ab Assays using Bio-Rad Elite Microplate Analyzer.]

BACKGROUND

In this study, we evaluated the performance of Elite microplate analyzer (Bio-Rad Laboratories, France) and the related assays (ULTRA line) for the detection of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV).

METHODS

Seroconversion panels, HBsAg positive/HBsAg negative (n=99/n=1,422), anti-HCV positive/negative (n=97/n=1,670), and anti-HIV positive/negative (n=112/n=1,704) samples were used to evaluate the performance of Monolisa HBsAg ULTRA, Monolisa HCV Ag-Ab ULTRA, and Genscreen ULTRA HIV Ag-Ab, respectively. The agreement of Elite microplate analyzer with CODA analyzer (Bio-Rad Laboratories, CA, USA) was also evaluated.

RESULTS

The detection limit of Monolisa HBsAg ULTRA was 0.034 IU/mL. For Monolisa HBsAg ULTRA, Monolisa HCV Ag-Ab ULTRA, and Genscreen ULTRA HIV Ag-Ab, diagnostic sensitivities were all 100%, diagnostic specificities were 100%, 99.8% and 99.9%, and total CVs (coefficients of variation) were 13.8-17.5%, 3.4-5.2%, and 7.5-9.5%, respectively. The agreement of Elite microplate analyzer with CODA analyzer was 99.5%.

CONCLUSIONS

The performance of Elite microplate analyzer and the related assays on analytical sensitivity, precision, early detection, diagnostic sensitivity and specificity was all adequate for a mass screening. However, further large multi-center studies should be performed to validate our results.

Low accuracy of the national reporting system of acute hepatitis C infection in Taiwan, 1995-2004

BACKGROUND AND AIM

This study attempted to clarify accuracy of acute hepatitis C (AHC) and its clinical characteristics.

METHODS

We reviewed 632 reported cases from national surveillance data of the Taiwan Center for Disease Control between 1995 and 2004, and reclassified diagnoses. A definite case was defined as alanine aminotransferase (ALT) > 10 x the upper limit of normal (ULN) with seroconversion of anti-hepatitis C virus antibody (anti-HCV). A probable case was defined as (i) seroconversion of anti-HCV and/or elevated ALT levels; or (ii) anti-HCV(+) but titers increased (from < 40 S/CO to >or= 40 S/CO) and ALT > 10 x the ULN. A suspected case was defined as initial anti-HCV(+) and ALT level > 10 x the ULN and/or jaundice. Excluded cases were defined as ALT levels less than 10 x ULN with initial positive anti-HCV Ab.

RESULTS

A total of 310 (49%) cases were confirmed as AHC; these included 95 (15%) definite and 215 (34%) probable cases. Higher incidence rates and accuracy of AHC were demonstrated in the southern area significantly if compared with northern, eastern and central areas, respectively (all P < 0.05). On comparison between blood centers and hospitals, more AHC cases were found in Southern Taiwan than in other areas (157/73 vs 24/40, P < 0.001), younger mean age (33.3 +/- 11.1 vs 49.3 +/- 16.4, P < 0.001), lower ALT levels (263.1 +/- 200.9 vs 1264.2 +/- 706.8, P < 0.001) and male predominance (191/39 vs 46/18, P = 0.046).

CONCLUSIONS

This study showed our reporting system over-estimated the AHC diagnosis, which is also a common issue worldwide. Greater efforts are needed to establish appropriate reporting systems, as well as more supplemental methods to distinguish between prevalent and incident cases.

Hepatitis C seropositivity is not a risk factor for sensory neuropathy among patients with HIV

BACKGROUND

Sensory neuropathy (SN) is common in patients with HIV. Hepatitis C (HCV) coinfection is often cited as an HIV-SN risk factor, but data to support this are lacking. This collaboration aimed to examine the association between HCV serostatus and SN risk among ambulatory HIV-positive patients.

METHODS

Patients with HIV were assessed in cross-sectional studies in Baltimore, Jakarta, Johannesburg, Kuala Lumpur, Melbourne, and Sydney for SN (defined by both supportive symptoms and signs). HCV seropositivity was assessed as an SN risk using a chi(2) test, followed by logistic regression modeling to correct for treatment exposures and demographics.

RESULTS

A total of 837 patients of African, Asian, and Caucasian descent were studied. HCV seroprevalence varied by site (Baltimore n = 104, 61% HCV+; Jakarta 96, 51%; Johannesburg 300, 1%; Kuala Lumpur 97, 10%; Melbourne 206, 16%; Sydney 34, 18%). HCV seropositivity was not associated with increased SN risk at any site, but was associated with reduced SN risk in Melbourne (p = 0.003). On multivariate analyses, the independent associations with SN were increasing age, height, and stavudine exposure. HCV seropositivity was not independently associated with an increased SN risk at any site, but associated independently with reduced SN risk in Baltimore (p = 0.04) and Melbourne (p = 0.06).

CONCLUSIONS

Hepatitis C (HCV) seropositivity was not associated with increased sensory neuropathy risk among HIV-positive patients at any site. While we were unable to assess HCV RNA or liver damage, the data suggest that HCV coinfection is not a major contributor to HIV-SN. HCV = hepatitis C; SN = sensory neuropathy.

Hepatitis C virus infection in blood donors from the state of Puebla, Mexico

Background

Worldwide, 130 million persons are estimated to be infected with HCV. Puebla is the Mexican state with the highest mortality due to hepatic cirrhosis. Therefore, it is imperative to obtain epidemiological data on HCV infection in asymptomatic people of this region. The objective of present study was to analyze the prevalence of antibodies and genotypes of hepatitis C virus (HCV) in blood donors from Puebla, Mexico.

Results

The overall prevalence was 0.84% (515/61553). Distribution by region was: North, 0.86% (54/6270); Southeast, 1.04% (75/7197); Southwest, 0.93% (36/3852); and Central, 0.79% (350/44234). Ninety-six donors were enrolled for detection and genotyping of virus, from which 37 (38.5%) were HCV-RNA positive. Detected subtypes were: 1a (40.5%), 1b (27.0%), mixed 1a/1b (18.9%), undetermined genotype 1 (5.4%), 2a (2.7%), 2b (2.7%), and mixed 1a/2a (2.7%). All recovered donors with S/CO > 39 were HCV-RNA positive (11/11) and presented elevated ALT; in donors with S/CO < 39 HCV-RNA, positivity was of 30.4%; and 70% had normal values of ALT. The main risk factors associated with HCV infection were blood transfusion and surgery.

Conclusions

HCV prevalence of donors in Puebla is similar to other Mexican states. The most prevalent genotype is 1, of which subtype 1a is the most frequent.

Common null variant, Arg192Stop, in a G-protein coupled receptor, olfactory receptor 1B1, associated with decreased serum cholinesterase activity

AIM

Non-functioning single nucleotide polymorphisms (nSNPs) that result in premature termination codons, that is null-alleles of the respective genes, may have phenotypic effects on clinical parameters. We conducted association studies involving several G-protein coupled receptors (GPCRs) that harbor nSNPs, using clinical parameters of liver function in a general population consisting of 2969 Japanese adults.

METHODS

SNP typings were performed with TaqMan and Invader assays. Quantitative associations between genotypes and clinical parameters were analyzed by analysis of variance. Linkage disequilibrium (LD) was tested by Haploview Version 3.3. Haplotype-based association was performed using the haplo.stats program.

RESULTS

A significant correlation (P = 0.0057) was identified between serum cholinesterase activity (CHE) and an nSNP (Arg192Stop) in the olfactory receptor (OR) 1B1 gene, a member of the GPCR gene family. This nSNP was associated with decreased serum CHE (P = 0.0013). LD analysis based on eight selected SNPs at the locus revealed three LD blocks. The Arg192Stop nSNP was located on the second LD block, which covered one-third of the 3'-portion of the gene.

CONCLUSION

These results suggested that the null-allele of OR1B1 might affect metabolism of serum cholinesterase in carriers of this nSNP.

Identified cases of acute hepatitis C from computerized laboratory database: a hospital-based epidemiological and clinical study

OBJECTIVE

Diagnosis of acute hepatitis C (AHC) relies on documented positive-seroconversion of antibody to hepatitis C virus (anti-HCV) that is infrequently encountered. To clarify the epidemiology and clinical course of AHC, we tried to find more AHC patients from a computerized laboratory database by using a supplemental criterion of rising anti-HCV titer.

METHODS

All the computerized laboratory databases of anti-HCV and alanine aminotransferase (ALT) were reviewed. Candidates for AHC were identified by either anti-HCV positive seroconversion, rise of anti-HCV titer (signal to cut-off ratio (S/CO) ratio < 40 to > or = 40), or spontaneous HCV RNA clearance. AHC cases and their matched chronic hepatitis C controls were interviewed by a case-control study concerning risk factors.

RESULTS

AHC was identified in 123 patients (68 men and 55 women; median age: 48.4+/-13.9 years), who had higher rates of recent surgery (p=0.037) and frequent injection therapy (p=0.036) compared to controls. Self-limited AHC was observed in 18 (19.1%, 95% confidence interval: 12.3-25.9%) of 94 AHC patients who had been followed for 6 months, with a higher bilirubin level (> or = 2 vs. < 2, p=0.007) compared to those evolved to chronic infection.

CONCLUSIONS

Screening of a laboratory database for anti-HCV and ALT might uncover more AHC candidates to disclose the epidemiology and clinical course of AHC.

Hla-Cw7 allele as predictor of favorable therapeutic response to interferon-alpha in patients with chronic hepatitis C

AIM

To evaluate the association between human leukocyte antigens (HLA) class I and therapeutic response to interferon-alpha in Croatian patients with chronic hepatitis C.

METHODS

HLA-A, -B, and -C genotyping was performed in 55 patients with sustained virological response and in 57 patients without sustained virological response to interferon-alpha therapy. Patients were treated in the period from 1998-2001 with interferon-alpha at a dose of 3 million units three times a week. Patients who became negative for hepatitis C virus RNA after 12 weeks of therapy completed 48 weeks of therapy.

RESULTS

There was no association between therapeutic outcome and frequency of HLA-A, as well as of HLA-B alleles. HLA-Cw7 was significantly more frequent in patients with than those without sustained virological response (27.0% vs 6.7%; P=0.011).

CONCLUSION

In Croatian patients with chronic hepatitis C, HLA-Cw7 is the predictor of sustained virological response to interferon-alpha therapy.

[Development of a Web-based Program to Calculate Sample Size for Evaluating the Performance of In Vitro Diagnostic Kits.]

BACKGROUND

Many studies evaluating the performance of in vitro diagnostic kits have been criticized for the lack of reliability. To attain reliability those evaluation studies should be preceded by sample size calculation ensuring statistical power. This study was intended to develop a web-based system to estimate the sample size, which was often neglected because it would require expert knowledge in statistics.

METHODS

For sample size calculation, we extracted essential parameters from the performance studies on the 3rd generation anti-hepatitis C virus (HCV) kits reported in the literature. We developed a system with PHP web-script language and MySQL. The statistical models used in this system were as follows; one sample without power consideration (model 1), one sample with power consideration (model 2), and two samples with power consideration (model 3).

RESULTS

Among the articles published between 1989 and 2005, 13 articles that evaluated the performance of anti-HCV kits were identified by searching with Medical Subject Headings (MeSH). The diagnostic sensitivity was 83-100% with a median of 145 samples (range; 12-1,091) and the specificity was 97-100% with a median of 1,025 samples (range; 33-4,381). The estimated sample size would be 280 in the model 1, 817 in the model 2, and 1,510 in the model 3, when we set 2% prevalence of HCV infection, 95% sensitivity of a conventional kit, 97% sensitivity of a new kit , 95% significance level (two-sided test), 2% allowable error, and 80% power.

CONCLUSIONS

Our study indicates that an insufficient sample size is still a problem in performance evaluation. Our system should be helpful in increasing the reliability of performance evaluation by providing an appropriate sample size.

Safety of blood supply in the Caribbean countries: Role of screening blood donors for markers of hepatitis B and C viruses

BACKGROUND

Blood transfusions carry risks of untoward reactions, including the transmission of infections, such as hepatitis B and C. Proper blood donor recruitment and selection, and adequate laboratory screening for infectious markers diminish the risk of transfusion-transmitted infections.

OBJECTIVES

To estimate the potential risk of acquiring transfusion-transmitted infections by hepatitis B or hepatitis C in 24 Caribbean countries during the period of 1996 to 2003.

STUDY DESIGN

Official national reports for 1996, 2000-2003 of the yearly number of blood donors, screening coverage, and prevalence of serological markers for infectious diseases were used to estimate the risk of patients receiving an HBV- or HCV-positive unit of blood, and of developing an infection after receiving a positive unit. Estimates of number of infections transmitted through transfusion and number of infections prevented by screening of blood were also obtained.

RESULTS

During the period analyzed, HBV screening coverage among blood donors was 100% in all countries with the exception of Grenada (0% in 1996) and Saint Lucia (99.5% in 2002). For HCV, only 10 countries reported universal screening in 1996, while 15 did in 2003. The number of countries that did not screen any units for HCV decreased from 11 in 1996 to five in 2003. In general, high prevalence rates of HBV (10-75 per 1000 donors) and HCV (7-19.3 per 1000 donors) markers were found in the majority of countries. We estimated that 235 infections by HCV (1:12471 donations) and two infections by HBV (1:1465373) were transmitted through transfusion because of lack of screening. On the other hand, screening of blood for transfusion prevented 21 005 HCV and 22 100 HBV infections.

CONCLUSIONS

Blood donor recruitment and coverage of screening for transfusion-transmitted infections, especially HCV, must be improved in the Caribbean countries.

Evaluation of three commercially available hepatitis C virus antibody detection assays under the conditions of a clinical virology laboratory

BACKGROUND

Most studies evaluating antibody detection assays are conducted on samples from healthy blood donors but not on samples of hospitalized patients which can show non-specific reactions.

OBJECTIVES

To compare the performance of three commercial automated assays for the detection of hepatitis C virus (HCV) antibodies, Monolisa anti-HCV Plus version 2, Axsym anti-HCV 3.0 and Vitros anti-HCV, on a population of hospitalized patients.

STUDY DESIGN

The specificity of the assays was prospectively evaluated in 2020 routine serum samples. In order to assign the serostatus of each sample, those giving positive or discordant results were further tested by three immunoblots and by RT-PCR (Roche). Moreover, the sensitivity was evaluated on eight commercial HCV seroconversion panels.

RESULTS

The Monolisa, Axsym and Vitros assays showed specificities of 99.64%, 99.12% and 99.33%, respectively. Concerning the sensitivity, among 49 samples, the number of positive results was 21, 24 and 24 for the Monolisa, Axsym and Vitros kits, respectively. The differences were not statistically significant at an alpha risk of 5%.

CONCLUSIONS

All assays appeared to be reliable for routine screening, but there were a surprising number of indeterminate samples that could not be resolved by confirmatory tests.

Évaluation de deux trousses commerciales EIA pour le diagnostic de l’hépatite C dans les conditions d’un laboratoire de virologie

BACKGROUND

Most studies which evaluate antibody detection assays are conducted on blood donors specimens, i.e healthy individuals. Sera collected in patients, vs healthy individuals, can make serological tests difficult because of possible non specific reactions interfering with serological tests. The aim of this work was to compare the specificity and the sensitivity of two commercial automated assays for the detection of hepatitis C virus antibody, Monolisa anti-HCV Plus on the Evolis automate (Biorad) and Axsym anti-HCV 3.0 (Abbott).

PATIENTS AND METHOD

The prospective study of specificity included 2020 routine serum samples sent to our virology laboratory. The sensitivity was established with eight commercially available HCV seroconversion panels.

RESULTS

The Monolisa and the Axsym assays showed a specificity of 99.64 and 99.12%, respectively. Of 49 specimens from eight commercially available HCV seroconversion panels, the number of positive results was 21 and 24 for the two tests, respectively.

CONCLUSION

A statistical analysis of specificity and sensitivity results proved no significant difference between the two tests. Nevertheless, the Monolisa kits could be preferred for its more homogeneous sensitivity than the Axsym test and for its apparent better specificity. The final choice of a kit should also take into account the easiness to perform and an optimal integration in the usual practice of the concerned laboratory.

Is it possible to diagnose acute hepatitis C virus (HCV) infection by a rising anti-HCV titre rather than by seroconversion?

The diagnosis of acute hepatitis C virus (HCV) infection relies on documented positive-seroconversion of HCV antibody (anti-HCV). Because of the detection of seroconversion at an earlier stage by second or third generation anti-HCV enzyme immunoassays (EIA), the diagnosis of acute hepatitis C (AHC) may be underestimated. The aim of this study was to evaluate whether rising anti-HCV titre could be used to diagnose AHC or not. Eighteen patients with a clinical diagnosis of acute hepatitis C were enrolled, including eight cases with documented seroconversion to anti-HCV and 10 cases with clinically suspected acute hepatitis C. Four chronic hepatitis C patients with acute exacerbation were selected as a control group. Serial sera were assayed with a third generation anti-HCV (AxSYM, version 3.0; Abbott, Chicago, IL, USA) and recombinant immunoblot assays (RIBA; Chiron HCV 3.0 Strip; Immunoblot, Emeryville, CA, USA) and the titre of anti-HCV expressed as signal/cutoff (S/CO) ratio and the RIBA patterns were correlated. Seven of eight documented AHC (one lacking the initial serum) and five of 10 clinically suspected AHC showed a rising pattern of S/CO values. The initial S/CO values on the first visit were less than 40 in 14 of 18 cases. The RIBA pattern shifted from negative/indeterminate to positive in five of seven documented AHC and 4 of 10 clinically suspected AHC cases. Fifteen of 18 cases had seroconversions of at least one antibody, whilst 85.7% showed a rising S/CO ratio. On the contrary, the S/CO ratio and RIBA pattern remained unaltered in chronic hepatitis C with acute exacerbation. The rise in S/CO was usually accompanied with an increase in the number of RIBA reactive bands and their intensity in acute hepatitis C patients. The rise in S/CO ratios using a third generation anti-HCV assay and the RIBA pattern might be used as a supplemental diagnostic criterion for acute HCV infection.

Prevention could be less cost-effective than cure: the case of hepatitis C screening policies in France

OBJECTIVES

To access the cost-effectiveness of French recommendations for hepatitis C virus (HCV) screening and the extent to which earlier identification of carriers may or not improve the cost-effectiveness of therapeutic strategies.

METHODS

Cost-effectiveness analysis were performed using decision-tree analysis and a Markov model. Four alternative strategies were compared: no screening and no treatment; initiation of HCV treatment after the diagnosis of cirrhosis; and two alternative strategies refer to the current French policies of HCV testing, i.e., two enzyme immunoblot assay (EIA) tests in series, or a polymerase chain reaction (PCR) analysis after the first positive EIA test. Costs were computed from the viewpoint of the health care system. The analysis has been applied to populations particularly at risk of infection, as well as the general population.

RESULTS

The "wait and treat cirrhosis" strategy was more cost-effective in the general population and in transfusion recipients. The incremental cost-effectiveness ratio of this strategy compared with baseline strategy was 3,476 of euros and Euro15,300 in respective cohorts. Considering the HCV screening strategy, the additional cost would be of Euro4,933 and Euro240,250 per additional year of life saved, respectively. In the intravenous drug user (IDU) population, the "two ElA" screening strategy was the more cost-effective alternative, with an additional cost of Euro3,825 per additional year of life saved.

CONCLUSIONS

HCV screening would be discarded for transfusion recipients but should be encouraged for IDUs and also for the general population, in which the additional cost of screening is an order of magnitude more acceptable.

Quantitative signal of anti-HCV by an automated assay predicts viremia in a population at high prevalence of hepatitis C virus infection

BACKGROUND AND AIMS

The diagnosis of ongoing hepatitis C virus (HCV) infection involves the detection of specific antibodies and of HCV-RNA. We aimed to assess the relationship between these two parameters in a representative sample of a population at high risk for HCV infection.

METHODS

Plasma and serum samples were respectively tested for HCV-RNA by a qualitative PCR (Cobas Amplicor HCV, Roche) and for HCV antibodies by a MEIA screening assay (AxSYM HCV 3.0, Abbott) and an immunoblot (Inno-LIA-III, Innogenetics).

RESULTS AND CONCLUSIONS

Out of 888 samples assayed, 579 (65.2%) were positive for HCV-RNA, while anti-HCV antibodies were detected respectively in 802 sera by AxSYM (90.3%) and in 783 by LIA (706 positive and 77 indeterminate, 88.2%). The anti-core antibodies displayed the best correlation with viremia, since they were present in 97.1% of the PCR+ samples, followed by anti-NS3 (90.2%) and anti-NS4 (89.6%). Only one HCV-RNA positive sample was negative by LIA and MEIA (early seroconversion). The AxSYM sample/cutoff (S/CO) values were directly correlated with the presence of HCV-RNA: a PCR positivity was found in 4.9% of samples with a S/CO < or =10, in 60.8% of samples with a S/CO between 11 and 50 and in 93.6% of cases with a S/CO >50, (P < 0.005). The immunoblot adds little, on a single specimen, to the information yielded by the AxSYM screening test. A suitable diagnostic algorithm for HCV in high-risk settings could be the anti-HCV screening by MEIA and a qualitative assay for HCV-RNA on samples with low reactivity.

Laboratory evaluation of a fully automated chemiluminescence immunoassay for rapid detection of HBsAg, antibodies to HBsAg, and antibodies to hepatitis C virus

The performance of a fully automated, random access, enhanced chemiluminescence immunoassay (Ortho/ECi) for the detection of antibody to hepatitis C virus (HCV) (anti-HCV), HBsAg, and antibody to HBsAg (anti-HBsAg), in human serum was compared to a Abbott second-generation enzyme immunoassay (EIA 2.0). The Ortho/ECi assays employ an immunometric technique with enhanced chemiluminescence for optimal assay performance. With regard to the study of clinical laboratory performance, six groups of sera prescreened with Abbott EIAs were assayed: anti-HCV-negative samples (n = 318), anti-HCV-positive samples (n = 177), anti-HBsAg-negative samples (n = 241), anti-HBsAg-positive samples (n = 239), HBsAg-positive samples (n = 158), and HBsAg-negative samples (n = 312). Sera with discrepant results in the two serological assays were resolved by confirmatory tests. Sera with indeterminate results by one or more confirmatory tests were evaluated by reviewing medical records. The overall concordance between the Ortho/ECi assay and the Abbott EIA were 97.78, 93.54, and 97.66% for anti-HCV antibodies, anti-HBsAg antibodies, and HBsAg, respectively. After resolving the discrepancies, the specificities of the new assay for anti-HCV and anti-HBsAg antibodies and HBsAg were 98.1, 92.8, and 100%, respectively. The sensitivities of the new assay for anti-HCV, anti-HBsAg, and HBsAg were 100, 98.8, and 97.4%, respectively. In conclusion, The Ortho/ECi assays for diagnosis of HCV and hepatitis B virus (HBV) infections are highly specific and sensitive assays. The rapid turnaround time, random access, full automation, and high throughput make it an effective assay system for clinical laboratory diagnosis of HCV and HBV infections.

Antiviral treatment responses in patients with chronic hepatitis C virus infection evaluated by a third generation anti-hepatitis C virus assay

Antibodies to hepatitis C virus (HCV) may decrease or disappear after viral clearance in treated or spontaneously resolved infection. We evaluated the usefulness of serial antibody assays in predicting the antiviral treatment responses. One hundred and four chronic hepatitis C patients who received 24 weeks of interferon and ribavirin combination therapy were assayed with a third generation enzyme immunoassay anti-HCV. The mean titre of anti-HCV decreased by more than 50% (from 89.5 +/- 10.8 to 43.6 +/- 17.5) at 48 weeks post-treatment in patients with a sustained virological response, while in nonsustained virological responders and nonresponders, the titres remained over 85% of the pretreatment level at 48 weeks post-treatment. There was a divergence of anti-HCV titres between sustained and nonsustained virological responders during 6-9 months. By using the ratio of 9-month to 6-month titres as an index and receiver operator characteristic curve analysis with the cut-off point set at 90%, we could differentiate sustained virological responders from nonsustained virological responders with a sensitivity and specificity of 91.7% and 90.9%, respectively, 3 months after treatment. The titre of this third generation anti-HCV decreased progressively in sustained virological responders and this assay may be used to monitor and predict antiviral treatment responses.