ActiTest accuracy for the assessment of histological activity grades in patients with chronic hepatitis C, an overview using Obuchowski measure.

BACKGROUND: ActiTest (AT) is a biomarker of liver necro-inflammatory histological activity validated in patients with chronic hepatitis C (HCV). AIM: The aim was to assess the accuracy of AT in comparison with alanine aminotransferase (ALT) the standard of care. METHODS: Methods used an integrated database of individual data and the new recommended Obuchowski measures. An updated "classical" meta-analysis of AT validation studies was also performed. The main end points were the area under the ROC curves (AUROCs) for the diagnosis of each histological activity grade defined using METAVIR scoring system. To avoid repeated tests and the spectrum effect of activity grades prevalence, the comparison of AT and ALT accuracies used the Obuchowski method. RESULTS: For the individual analysis, a total of 1250 patients were included and for the meta-analysis six studies (2017 patients) were included. The overall accuracy of AT for the diagnosis of any activity grade (Obuchowski measure=0.850) was significantly higher than the accuracy of ALT (Obuchowski measure=0.837; P=0.009). The updated standard meta-analysis confirmed the accuracy of AT (p<0.0001) both in independent AUROC=0.79 (95% CI, 0.73-0.85) and in non independent studies AUROC=0.74 (95% CI, 0.67-0.81). CONCLUSIONS: The accuracy of AT for grading the necro-inflammatory activity of patients with HCV was significantly higher than ALT serum activity alone, the standard biomarker.

Evaluation of FibroTest-ActiTest in children with chronic hepatitis C virus infection.

FibroTest-ActiTest (FT-AT) has been validated in adults with chronic hepatitis C virus (HCV) infection as a noninvasive alternative to liver biopsy (LB), but there are few data of its use in children. The objective of the present study was to evaluate FT-AT in children with HCV infection and to compare FT-AT analysis with liver histology. A total of 43 serum samples from 38 children with chronic HCV infection were analyzed retrospectively. Histological evaluation was performed according to the METAVIR scoring system. In 16 of the children, 21 serum samples were tested with FT-AT and compared to 21 LB (serum/LB pairs) in nontransplanted and liver-transplanted children. FT-AT was also measured in 22 infected children without LB and in 50 healthy controls. FT-AT values in controls were comparable to those of healthy adults, validating the adult FT-AT parameters in children. In most infected children (74%), the FT-AT score was

Methodological aspects of the interpretation of non-invasive biomarkers of liver fibrosis: a 2008 update.

This review summarizes the methodological aspects of the interpretation of non-invasive biomarkers in liver fibrosis. A scoring system has been updated to better compare the quality of fibrosis biomarkers. Several methodological issues are related to the classical methodology using biopsy, as this is considered the gold standard. However, from evidence-based data, it appears that the methodology needs to change to prevent flawed conclusions among key opinion leaders as well as in obsolete guidelines. As waiting for the perfect biomarker for the diagnosis of advanced fibrosis to come along is probably a waste of time, in the meantime, methods can be improved. The main proposals for improving the methodology are, to take into account the spectrum bias, to assess accuracy between adjacent stages, to compare biomarkers in the same patient, to assess the cause of failure among discordant cases and to use specific statistical methods adapted for imperfect gold standards.

Relationship between the Fibrotest and portal hypertension in patients with liver disease.

BACKGROUND: The best technique to estimate portal hypertension (PHT) is to measure the hepatic venous pressure gradient (HVPG), which is an invasive method. AIM: To assess the relationship between the Fibrotest (Biopredictive, Paris, France) and the presence and degree of PHT in patients with liver disease, and to determine if the Fibrotest can diagnose severe PHT, defined by HVPG >or= 12 mmHg, in cirrhotic patients. METHODS: Patients who underwent a transjugular liver biopsy were prospectively included. HVPG was measured, and classification of histological lesions assessed. The same day, blood samples for Fibrotest were performed. RESULTS: A total of 130 patients were included (no or minimal fibrosis: 12%, moderate fibrosis 17%, cirrhosis 71%). There was a significant correlation between Fibrotest and HVPG (Pearson correlation coefficient = 0.58, P < 0.0001), also weaker in cirrhotic patients (Pearson correlation coefficient = 0.24, P = 0.02). In cirrhotic patients, Fibrotest was significantly higher when there was a severe PHT (0.87 +/- 0.15 vs. 0.73 +/- 0.14, respectively, P = 0.02). The areas under the receiver operating characteristic curves for the diagnosis of severe PHT was 0.79 +/- 0.07, not different from that of platelets and Child-Pugh score. CONCLUSION: In patients with liver disease or cirrhosis, Fibrotest is correlated with the presence and degree of PHT. Other studies are needed to confirm these results, especially in non-decompensated cirrhotic patients.

Variability of the area under the receiver operating characteristic curves in the diagnostic evaluation of liver fibrosis markers: impact of biopsy length and fragmentation.

BACKGROUND: The area under the receiver operating characteristic (ROC) curve is widely used as an estimate of the diagnostic value for fibrosis markers. Biopsy length and fragmentation are known as risk factors of false positive or false negative of biopsy but their quantitative impact on area under the receiver operating characteristic curve variability has not been assessed. AIM: To assess these relationships to better compare the fibrosis markers. METHODS: The area under the ROC curves of FibroTest for the diagnosis of fibrosis was estimated in patients with chronic hepatitis C using an integrated database including 1312 patients with FibroTest and biopsy. To take into account the biopsy length, we used two adjustment factors: one in which an observed area under the ROC curve could be adjusted according to the relative area under the receiver operating characteristic curve of a biopsy of a given length vs. the entire liver and one taking into account the prevalence of each fibrosis stage defining advanced and non-advanced fibrosis. RESULTS: The mean biopsy length was smaller for cirrhosis (F4, 16 mm) vs. F3, (18 mm, P=0.01) and F0 (19 mm, P=0.01). The mean number of fragments was higher for cirrhosis (F4=4.1 fragments) vs. all the other stages (F0=1.9, F1=1.9, F2=1.9, F3=2.3; P<0.001 vs. F4). The FibroTest area under the ROC curves for the diagnosis of advanced fibrosis, adjusted for stages' prevalence, ranged from 0.80 to 0.98 depending on biopsy length and fragmentation, respectively. CONCLUSION: The comparison of the area under the ROC curves of fibrosis markers should take into account the biopsy length and fragmentation.

Screening for liver disease using non-invasive biomarkers (FibroTest, SteatoTest and NashTest) in patients with hyperlipidaemia.

BACKGROUND: Mortality related to complications of cirrhosis is increasing in patients with insulin-resistance factors. Hyperlipidaemic patients have multiple risk factors of insulin resistance. It is impossible to perform liver biopsy in such a large number of hyperlipidaemic patients to identify patients with advanced liver fibrosis or with steatohepatitis (non-alcoholic steatohepatitis, NASH). AIMS: To use the non-invasive biomarkers, FibroTest (FT), SteatoTest and NashTest, and to assess the prevalence of advanced liver disease in a large population of hyperlipidaemic patients. METHODS: A consecutive cohort of hyperlipidaemic patients was followed prospectively in a lipid centre and the sera were analysed retrospectively. RESULTS: A total of 2834 subjects were included: 1909 hyperlipidaemic patients and 925 blood donors (BD). Advanced fibrosis was identified by FT in 53/1909 (2.8%) hyperlipidaemic patients vs. 0/925 BD (0%) (P < 0.0001); advanced steatosis in 569/1893 hyperlipidaemic patients (30.1%) vs. 8/164 (4.9%) BD (P < 0.0001) and NASH in 132/1893 (7%) vs. 0/164 (0%), respectively (P < 0.0001). There was a highly significant and linear association between the number of metabolic syndrome factors and liver disease prevalence - the highest being for type 2 diabetics: advanced steatosis 66%, NASH 24% and advanced fibrosis 6%. CONCLUSIONS The prevalence of fibrosis, steatosis and NASH in hyperlipidaemic patients appears to be high (3%, 30% and 7%, respectively). Biomarkers could be useful for screening of advanced fibrosis and NASH in patients with several metabolic syndrome factors, to prevent liver mortality.

A prospective assessment of an 'a la carte' regimen of PEG-interferon alpha2b and ribavirin combination in patients with chronic hepatitis C using biochemical markers.

In therapy with standard interferon and ribavirin, five independent risk factors (RF) were predictive of relapse. The aim was to prospectively validate an a la carte regimen of pegylated interferon (PEG-IFN) alpha2b 1.5 microg/kg and ribavirin 11 mg/kg [PEG-IFN-ribavirin (PEG-IFN-R)], taking into account these five risk factors in order to determine whether to continue an additional 24 weeks of treatment in polymerase chain reaction (PCR) negative patients after 24 weeks. Treatment was stopped after 24 weeks in PCR positive patients. The same regimen was continued in PCR negative patients for an additional 24 weeks if patients had two or more RF. FibroTest and ActiTest assessed the impact of treatment on the histological features from baseline to end of follow-up. A total of 96 patients were included; 84 (87.5%) had at least two RF and 12 (12.5%) had no or one RF. A total of 70 patients were sustained virologic response (SVR; 73%), 19 were nonresponders (20%) and seven were relapsers (7%). The SVR in genotypes 2 or 3 was 85% (34/40) vs 64% in other genotypes (36/56; P = 0.02). There was a decrease (P = 0.003) in fibrosis as estimated by FibroTest, from 0.38 +/- 0.03 (mean +/- SE) at baseline to 0.33 +/- 0.03 at the 12-week follow-up, and a decrease in activity as estimated by ActiTest, from 0.49 +/- 0.02 to 0.19 +/- 0.03 (P < 0.0001). Improvement in activity was already significant at 12 weeks, even in virologic nonresponders. This study confirms that an a la carte regimen which takes into account not only genotype but also baseline viral load, fibrosis stage, gender and age, is efficient for the PEG-IFN-R combination. It achieves a 73% SVR and a significant decrease in fibrosis and activity as estimated by biochemical markers.

[Alpha 2 macroglobulin immunoturbidimetric assays (DakoCytomation reagents) on Roche Diagnostic analysers (Modular P, Cobas Integra). Application to FibroTest-Actic-Test]. / Dosage immunoturbidimétrique de l'alpha 2 macroglobuline (réactifs DakoCytomation) sur les automates Roche Diagnostics (Modular P, Cobas Intégra). Application au FibroTest-ActiTest).

BACKGROUND: Alpha2Macroglobulin (A2M) measure showed a revival since it was introduced into FibroTest-ActiTest-Fibro (FT-AT-Fibro) algorithm. More often than not, this assay is performed in immunonephelemetry. Progresses in the comprehension of fibrosis dynamics and better treatment efficacy follow-up will increase FT-AT-Fibro prescriptions. Despite efforts to standardize methods of enzymatic activity measure and proteins measure, we still observe important interlaboratory and intersystem variability. AIM: The primary aim of the study is to validate immunoturbidimetric measure of A2M on Modular P and Cobas Integra analysers (Roche Diagnostics) in utility channel using DakoCytomation reagents in order to extend the analytical system range allowed to measure A2M. The secondary aim of the study is to verify transferability of the six FT-AT composants (A2M, haptoglobin, apolipoprotein A1, total bilirubin, GGT and ALT) to Roche Diagnostics equipment by comparing with results measured on the reference system. RESULTS: A2M measures (n = 146) showed linearity, repetitiveness and were reproducible. Readjustments to adapt A2M measures were required. A corrector factor of 0.84 for Modular P and of 0.87 for Cobas Integra was introduced in order to readjust the immunoturbidimetric method to the immunonephelemetric method. The rationale of proposed corrector factors is based on the use of Dade Behring and DakoCytomation reagents (antisera and calibrant). Biologist vigilance is required to point out modifications or variations in reagents that could be done by the company. The six parameters results transferability from the reference system to Roche Diagnostics was demonstrated by statistic analysis. FT-AT showed excellent correlations to the reference system for Modular P and Cobas Integra analysers. In this study no difference more than 0.11 was recorded and only few subjects had differences between 0.05 and 0.10. Therefore this very low inter-analysers variability has no significant clinical impact. CONCLUSION: This study showed that the analytical system made of Modular P, Cobas Integra, Roche Diagnostics and DakoCytomation reagents can be used for FibroTest-ActiTest-Fibro parameters assessment. Their statistical and clinical variability were acceptable compared to the reference system.

[Results transferability on RXL, ARX, X-Pand, BN2 (Dade Behring) and modular DP (Roche Diagnostics) analysers: application to component assays of fibrotest and Actitest]. / Transférabilité des résultats entre les automates RXL, ARX, X-Pand, BN2 (Dade Behring) et le Modular DP (Roche Diagnostics): application aux paramètres des Fibrotest et Actitest.

The follow up of patients with chronic liver diseases and the data from multicentric clinical studies are affected by the variability of assay results for the same parameter between the different laboratories. Today, the main objective in clinical chemistry throughout the world is to harmonise the assay results between the laboratories after the confirmation of their traceability, in relation to defined reference systems. In this context, the purpose of our study was to verify the homogeneity of haptoglobin, apolipoprotein A1, total bilirubin, GGT activity, ALAT activity results, which are combined in Fibrotest and Actitest, between Dimension Analysers RXL, ARX and X-PAND (Dade Behring Society). Moreover, we verified the transferability of Fibrotest and Actitest results between the RXL, and either the BN2 (haptoglobin and apolipoprotein A1) or the Modular DP (total bilirubin, GGT and ALAT activity concentrations). The serum samples from 150 hospitalised patients were analysed on the different analysers. Specific protein assays were calibrated using solutions standardised against reference material on Dimension and BN2 analysers. Total bilirubin assays were performed by a diazoreaction on Dimension and Modular DP analysers. The GGT and ALAT activity measurements on the Dimension analysers were performed in accordance with the reference methods defined by the International Federation of Clinical Chemisty and Laboratory Medicine (IFCC). On the Modular, enzyme activity measurements were performed according to the Szasz method (L-gamma- glutamyl-4-nitroanilide as substrate) modified by Persijn and van der Slik (L-gamma- glutamyl-3-carboxy- 4-nitroanilide as substrat) for GGT and according to the IFCC specifications for ALAT. The methods of enzymatic activity measurement were calibrated on the Modular only. Liver fibrosis and necroinflammatory activity indices were determined using calculation algorithms, after having adjusted each component's result of Fibrotest and Actitest for gender and age. Our study has shown, for each parameter, harmonious results between the Dimension analysers and between RXL and BN2- Modular DP. Disregarding alpha-2 macroglobulin which cannot be assayed on RXL, the results of Fibrotest and Actitest were similar as performed on BN2- Modular DP and RXL.

[Influence of pyridoxal phosphate in measuring aminotransferases activities in patients with viral hepatitis]. / Effet du phosphate de pyridoxal dans la mesure des activités aminotransférases chez les patients avec hépatite virale.

Effect of a pyridoxal phosphate (PP) supplementation of reagents used for ALT and AST measurement was studied in serum of 20 patients suffering from viral hepatitis. Measurements of enzyme activities were carried out at 37 degrees C, using an automate (AU 600, Olympus). Significant differences (p < 0.0001) were observed both for ALT and AST, meanwhile they were more marked for ALT than for AST. This difference was associated with a strong interindividual variability regarding PP activation effect on ALT. In conclusion, aminotransferase measurements should be carried out with a reagent supplemented with PP, when the enzyme activity is used to evaluate a cytolysis. The same recommendation applies when ALT results are integrated into various combinations developed for the evaluation of liver status.

Biochemical markers of liver fibrosis in patients infected by hepatitis C virus: longitudinal validation in a randomized trial.

A liver fibrosis index was recently prospectively validated in a cross-sectional study where patients infected by hepatitis C virus (HCV) had only one biopsy and no longitudinal follow-up. The aim of this study was to retrospectively assess the diagnostic value of this index in patients included in a randomized trial of interferon (IFN) using repeated measurements, two biopsies and hyaluronic acid as a comparative reference. One-hundred and sixty-five patients who had had two interpretable liver biopsies and at least one stored serum sample before IFN treatment were selected. Seventy-eight patients received 3 MU of IFN-alpha thrice weekly for 24 weeks and 87 followed a reinforced regimen for 48 weeks. A fibrosis index combining five biochemical markers (alpha2-macroglobulin, haptoglobin, apolipoprotein A1, gamma-glutamyl transpeptidase (GGT) and total bilirubin adjusted for gender and age) as well as hyaluronic acid was assessed on 461 samples available at baseline, at the end of treatment and at the end of follow-up (72 weeks). There was a significant decrease of the fibrosis index score among the 17 sustained virologic responders, from 0.33 +/- 0.06 (mean +/- SE) at baseline to 0.18 +/- 0.06 at 72 weeks in comparison with 92 nonresponders (from 0.41 +/- 0.03 at baseline to 0.44 +/- 0.03 at 72 weeks; P < 0.001) and in comparison with 56 relapsers (from 0.36 +/- 0.03 at baseline to 0.32 +/- 0.03 at 72 weeks; P=0.05). No significant differences were observed for hyaluronic acid.Hence, this fibrosis index could be used as a surrogate marker of the antifibrotic effect of treatments in patients with chronic hepatitis C.