Viral dominance patterns in chronic hepatitis delta determine early response to interferon alpha therapy.

Chronic hepatitis D is caused by coinfection of hepatitis B and hepatitis D virus. While HDV is the dominant virus over HBV in the majority of cases, mechanisms and consequences of viral dominance are largely unknown. We aimed to investigate associations between viral dominance patterns and patients' characteristics and inflammatory features; 109 HDV-infected patients treated with PEG-IFNa-2α within the international multicentre, prospective HIDIT-2 trial were studied. Patients were classified as D- or B-dominant if the viral load of one virus exceeded that of the other virus by more than 1log10 . Otherwise, no viral dominance (ND) was described. We used Luminex-based multiplex technology to study 50 soluble immune mediators (SIM) in pretreatment samples of 105 HDV RNA-positive patients. Dominance of HDV was evident in the majority (75%) of cases. While only 7% displayed B-dominance, 17% showed nondominance. D-dominance was associated with downregulation of 4 interleukins (IL-2ra, IL-13, IL-16 and IL-18) and 5 chemokines/cytokines (CTACK (CCL27), MCP-1 (CCL2), M-CSF, TRAIL and ICAM-1) while no analyte was increased. In addition, D-dominance could be linked to a delayed HDV RNA response to pegylated interferon as patients with B-dominance or nondominance showed higher early HDV RNA responses (61% at week 12) than D-dominant patients (11%; P < .001). In conclusion, this study revealed unexpected effects of viral dominance on clinical and immunological features in chronic hepatitis delta patients. Individualizing PEG-IFNa-2α treatment duration should consider viral dominance. Overall, our findings suggest an activated but exhausted IFN system in D-dominant patients.

Cross-genotype-specific T-cell responses in acute hepatitis E virus (HEV) infection.

Hepatitis E is an inflammatory liver disease caused by infection with the hepatitis E virus (HEV). In tropical regions, HEV is highly endemic and predominantly mediated by HEV genotypes 1 and 2 with >3 million symptomatic cases per year and around 70 000 deaths. In Europe and America, the zoonotic HEV genotypes 3 and 4 have been reported with continues increasing new infections per year. So far, little is known about T-cell responses during acute HEV genotype 3 infection. Therefore, we did a comprehensive study investigating HEV-specific T-cell responses using genotypes 3- and 1-specific overlapping peptides. Additional cytokines and chemokines were measured in the plasma. In four patients, longitudinal studies were performed. Broad functional HEV-specific CD4(+) and CD8(+) T-cell responses were detectable in patients acutely infected with HEV genotype 3. Elevated of pro- and anti-inflammatory cytokine levels during acute HEV infection correlated with ALT levels. Memory HEV-specific T-cell responses were detectable up to >1.5 years upon infection. Importantly, cross-genotype HEV-specific T-cell responses (between genotypes 1 and 3) were measurable in all investigated patients. In conclusion, we could show for the first time HEV-specific T-cell responses during and after acute HEV genotype 3 infection. Our data of cross-genotype HEV-specific T-cell responses might suggest a potential role in cross-genotype-specific protection between HEV genotypes 1 and 3.

Development and evaluation of a baseline-event-anticipation score for hepatitis delta.

Hepatitis delta is considered the most severe form of viral hepatitis, but variables associated with disease progression are poorly defined. This study aimed to identify risk factors associated with worse clinical outcome in patients with hepatitis delta and to develop a clinical score to determine their risk of experiencing liver-related morbidity or mortality. We followed 75 HBsAg-anti-HDV-positive patients with hepatitis delta for up to 16 years (median 5 years). The baseline-event-anticipation score (BEA score) was developed based on variables associated with the development of liver-related clinical complications. Age, region of origin, presence of cirrhosis, albumin, INR, hyperbilirubinemia and thrombocytopenia were all associated with the development of an event in the training cohort. The BEA score included age, sex, region of origin, bilirubin, platelets and INR. Points were allocated according to hazard ratios, and three risk groups were defined: BEA-A mild risk, BEA-B moderate risk and BEA-C high risk. Hazard ratios of BEA-B and BEA-C patients for liver-related clinical endpoints were 9.01 and 25.27 vs BEA-A with an area under curve of the receiving operating characteristic curve of 0.88. The accuracy of the BEA score was confirmed in two independent validation cohorts followed in Barcelona (n = 77) and Düsseldorf (n = 62). Delta hepatitis is associated with a very severe long-term outcome. The BEA score is easy to apply and predicts with a very high accuracy the development of liver-related complications in patients with hepatitis delta.

Course and treatment of chronic hepatitis E virus infection in lung transplant recipients.

OBJECTIVE: Persistent hepatitis E virus (HEV) infections have been described in various transplant cohorts. However, the frequency and the course of HEV infection in lung transplant recipients (Lu-Tr) are not well defined. METHODS: We retrospectively analyzed serum from 95 Lu-Tr for HEV RNA and anti-HEV immunoglobulin-G (IgG) (with the MP assay). Anti-HEV seroprevalence was compared to that of 537 healthy individuals. Prospective HEV screening was subsequently initiated in Lu-Tr. RESULTS: Elevated liver enzymes were observed in 44/95 (46.3%) patients. Anti-HEV IgG was present in 5/95 patients (5.3%), revealing a slightly higher prevalence compared to controls (2%, 11/537; P = 0.07). Chronic HEV infection with detectable viral replication was confirmed by polymerase chain reaction in 3 (3.2%) patients, all of whom demonstrated clinical and biochemical features of active liver disease (maximum alanine aminotransferase [ALTmax ] 89, 215, and 270 IU/L, respectively). One patient had died from multi-organ failure in combination with liver cirrhosis before HEV diagnosis. Two additional patients with chronic hepatitis E were identified during prospective screening (ALTmax 359 and 318 IU/L). All patients still alive commenced ribavirin therapy for 5 months, with dose adjustment (400-600 mg/day) according to renal function and hemoglobin level. Sustained resolution of HEV infection occurred in 2 patients. One patient is still under treatment, and the fourth died from graft failure considered unrelated to ribavirin therapy. CONCLUSION: Chronic hepatitis E should be considered in the differential diagnosis of elevated liver enzymes, which are commonly seen in Lu-Tr. We observed 1 case of end-stage liver cirrhosis and death in an HEV-infected subject, who was not treated with ribavirin. Given this potentially devastating consequence, ribavirin therapy of persistent HEV infection appears to be acceptably safe and effective in Lu-Tr. However, larger prospective studies are warranted.

Evolutionary history of the Afro-Madagascan Ixora species (Rubiaceae): species diversification and distribution of key morphological traits inferred from dated molecular phylogenetic trees.

BACKGROUND AND AIMS: Previous work on the pantropical genus Ixora has revealed an Afro-Madagascan clade, but as yet no study has focused in detail on the evolutionary history and morphological trends in this group. Here the evolutionary history of Afro-Madagascan Ixora spp. (a clade of approx. 80 taxa) is investigated and the phylogenetic trees compared with several key morphological traits in taxa occurring in Madagascar. METHODS: Phylogenetic relationships of Afro-Madagascan Ixora are assessed using sequence data from four plastid regions (petD, rps16, rpoB-trnC and trnL-trnF) and nuclear ribosomal external transcribed spacer (ETS) and internal transcribed spacer (ITS) regions. The phylogenetic distribution of key morphological characters is assessed. Bayesian inference (implemented in BEAST) is used to estimate the temporal origin of Ixora based on fossil evidence. KEY RESULTS: Two separate lineages of Madagascan taxa are recovered, one of which is nested in a group of East African taxa. Divergence in Ixora is estimated to have commenced during the mid Miocene, with extensive cladogenesis occurring in the Afro-Madagascan clade during the Pliocene onwards. CONCLUSIONS: Both lineages of Madagascan Ixora exhibit morphological innovations that are rare throughout the rest of the genus, including a trend towards pauciflorous inflorescences and a trend towards extreme corolla tube length, suggesting that the same ecological and selective pressures are acting upon taxa from both Madagascan lineages. Novel ecological opportunities resulting from climate-induced habitat fragmentation and corolla tube length diversification are likely to have facilitated species radiation on Madagascar.

Chronic hepatitis e in heart transplant recipients.

Chronic courses of hepatitis E virus (HEV) infections have been described in immunosuppressed patients. We aimed to study the role of HEV infections in heart transplant recipients (HTR). 274 HTR were prospectively screened for HEV infection using an anti-HEV-IgG ELISA and HEV-PCR. In addition, 137 patients undergoing cardiac surgery (non-HTR) and 537 healthy subjects were studied cross-sectionally. The anti-HEV-IgG seroprevalence was 11% in HTR, 7% in non-HTR and 2% in healthy controls (HTR vs. healthy controls p<0.0001; non-HTR vs. healthy controls p<0.01). Anti-HEV tested positive in 4.0% in control cohorts of other immunocompromised patients (n = 474). Four HTR (1.5%) were chronically infected with HEV as shown by HEV-PCR and all four patients had liver transaminases of >200 IU/L and histological or clinical evidence of advanced liver disease. In three patients ribavirin treatment was successful with a sustained biochemical and virological response while treatment failed in one cirrhotic patient after ribavirin dose reduction. Heart transplant recipients and patients undergoing cardiac surgery have an increased risk for HEV infections. Chronic hepatitis E may explain elevated liver enzymes in heart transplant recipients. Treatment of HEV infection with ribavirin is effective but the optimal dose and duration of ribavirin therapy remains to be determined.

Chronic hepatitis E in hematopoietic stem cell transplant patients in a low-endemic country?

Cases of chronic hepatitis E have been described in patients after kidney and liver transplantation. In addition, hepatitis E virus (HEV) reactivation was reported after hematopoietic stem cell transplantation (HSCT). We here evaluated if HEV infection might explain elevated liver enzymes in a well selected cohort of allogeneic HSCT patients with biochemical evidence of hepatitis (n = 52). Of note, none of the subjects tested positive for HEV RNA, including 2 HSCT patients who had been infected with HEV already before transplantation. Thus, both chronic courses of HEV infections and HEV reactivations seem to be rather rare events in HSCT patients in a non-endemic country.

Hepatitis E: an emerging infectious disease in Germany?

Increased frequencies of HEV infections have been reported in several industrialized countries. We suggest that this finding might be explained by a better awareness of the disease and not by an increased incidence. Although reported HEV infections increased more than 6-fold in Germany in recent years, the seroprevalence remained unchanged (2 %).

Dietary amino acids fed in free form or as protein do differently affect amino acid absorption in a rat everted sac model.

In the present study, the effect of free amino acid (FAA) diets on the intestinal absorption rate of methionine and leucine was studied 'ex vivo' with rats adapted for different periods of time to the diets, using the everted sac method. The adaptation period to the 21% FAA diet with an amino acid content based on casein was either, 0 (no adaptation, N-ADA), 5 (short-term adaptation, ST-ADA), or 26-33 days (long-term adaptation, LT-ADA). Within the ST-ADA and the LT-ADA groups, three different levels of methionine were included: 50%, 100% and 200% of the level normally present in casein. All diets were iso-nitrogenous and iso-caloric. After the adaptation period (0, 5, or 26-33 days), intestinal everted sacs were prepared. Methionine or leucine was added to the medium as transport substrate. The methionine absorption rate of the rats of the LT-ADA groups was higher than that of the N-ADA groups. Furthermore, adaptation to 200% dietary methionine levels caused a significantly slower leucine absorption compared to the 100%, and 50% group. Methionine absorption was similar in the 100% and 200% groups, but the absorption of methionine in the 50% group was enhanced in the distal part of the intestines. We concluded that in response diets with 21% FAAs as only amino acid source, amino acid absorption is decreased to avoid toxic effects of high levels of methionine in the circulation.

Dental implants in patients with orofacial clefts: a long-term follow-up study.

Aim of this study was to determine the success of implants that were inserted in patients with cleft of the lip, alveolus and palate (CLAP) and to identify prognosis-relevant factors. In a prospective evaluation, 75 implants inserted in combination with bone grafting at cleft sites of 45 patients were examined. The observation period extended 5.5 years in average (minimum 1.5, maximum 11.3 years). Implant success was evaluated clinically and radiographically and was compared to age- and gender-matched control groups. Statistic assessment included Kaplan-Meier survival analysis, Log rank tests and Cox regression analysis. In total, 10 implants were lost in 8 patients, resulting in an implant survival rate of 82.2% at the end of the observation period. Patient-related parameters of age, gender or type of cleft had no significant influence. The length of an implant was significantly related to an improved survival rate (P<0.01). Implant survival was less in CLAP patients when compared to implant insertions in a non-cleft control group, but improved when compared to patients with bone grafting for other indications. It is concluded that implants combined with bone grafting can offer a reliable alternative in patients with CLAP.

Hepatitis B core-related antigen (HBcrAg) levels in the natural history of hepatitis B virus infection in a large European cohort predominantly infected with genotypes A and D.

Hepatitis B core-related antigen (HBcrAg) has been suggested as an additional marker of hepatitis B virus (HBV) infection. HBcrAg combines the antigenic reactivity resulting from denatured hepatitis B e antigen (HBeAg), HBV core antigen and an artificial core-related protein (p22cr). In Asian patients, high levels of HBcrAg have been suggested to be an independent risk factor for hepatocellular carcinoma, while low levels could guide safe cessation of treatment with nucleos(t)ide analogues. We here studied HBcrAg levels in different phases of HBV infection in a large European cohort predominantly infected with genotypes A and D: HBeAg-positive immune tolerance (n = 30), HBeAg-positive immune clearance (IC) (n = 60), HBeAg-negative hepatitis (ENH) (n = 50), HBeAg-negative inactive/quiescent carrier phase (c) (n = 109) and acute hepatitis B (n = 8). Median HBcrAg levels were high in the immune tolerance and immune clearance phases (8.41 and 8.11 log U/mL, respectively), lower in ENH subjects (4.82 log U/mL) but only 2.00 log U/mL in ENQ subjects. Correlation between HBcrAg and HBV DNA varied among the different phases of HBV infection, while HBcrAg moderately correlated with hepatitis B surface antigen in all phases. ENQ patients had HBcrAg levels <3 log U/mL in 79%, in contrast to only 12% in the ENH group. HBcrAg levels vary significantly during the different phases of HBV infection. HBcrAg may serve as valuable marker for virus replication and reflect the transcriptional activity of intrahepatic cccDNA. In HBeAg-negative patients, HBcrAg may help to distinguish between inactive carriers (ENQ) and those with active disease (ENH).

Quality of life in ALS depends on factors other than strength and physical function.

OBJECTIVES: To study patients with ALS to determine the following: 1) the relationship between physical function and quality of life (QOL); 2) the instruments that best reflect patients' own ratings of QOL; and 3) whether spiritual/religious factors play a role in determining QOL. METHODS: The authors prospectively studied 96 patients with ALS using several instruments, including the McGill Quality of Life (MQOL) instrument, the Idler Index of Religiosity, the Sickness Impact Profile (SIP)/ALS-19, and several measures of strength and physical function. RESULTS: QOL as assessed by patients (MQOL single item score) did not correlate with measures of physical function and strength, but correlated with the total MQOL score (p < 0.0005), the psychological and existential subscores of MQOL (p < 0. 0005), the support subscore of MQOL (p = 0.001), and the total Idler score (p = 0.001). In contrast, correlations between SIP/ALS-19 and these measures were not significant, although SIP/ALS-19 correlated with measures of physical function and strength. CONCLUSIONS: QOL, as assessed by the patient with ALS, does not correlate with measures of strength and physical function, but appears to depend on psychological and existential factors, and thus may be measured well by the MQOL scale. Spiritual factors and support systems appear to play roles as well. SIP/ALS-19 is a good measure of physical function, but not of overall QOL.

Quality of life in ALS is maintained as physical function declines.

OBJECTIVES: To study patients with ALS to determine how physical function, quality of life (QOL), and spirituality or religiousness change over time, and what relationship these changes have to one another. METHODS: Sixty patients with ALS were studied prospectively. They were assessed at baseline, 3 months, and 6 months, using questionnaires designed to measure general quality of life (McGill Quality of Life questionnaire), religiosity (Idler Index of Religiosity), ALS-specific health-related quality of life (SIP/ALS-19), and ALS-specific function (ALS functional rating scale). RESULTS: A two-way repeated measures multivariate analysis of variance revealed that both the passage of time and the specific QOL scales used were factors in predicting patient quality of life (F[1, 59]= 9.87, p < 0.003 and F[3, 177]= 16.90, p < 0.001) Despite a progressive decline in physical function as measured by the ALS-specific function score, the general QOL and religiosity scores changed little. In contrast, the ALS-specific health-related QOL score declined in parallel with the ALS-specific function score. CONCLUSIONS: QOL in patients with ALS appears to be independent of physical function, which agrees with a previous cross-sectional study. The ALS-specific health-related QOL score is primarily a measure of physical function. QOL instruments that assess spiritual, religious, and psychological factors produce different results than those obtained using measures of physical function alone.

Heat shock- and ethanol-induced ionic changes in C6 rat glioma cells determined by NMR and fluorescence spectroscopy.

The effects of two different stressors, heat shock (HS; 44 degrees C, 20 min) and ethanol (1.2 M, 60 min), on ion content and membrane potential were investigated in C6 rat glioma cells. Both treatments were previously shown to induce the HS response [26]. Intracellular pH (pH(i)), sodium ion concentration ([NA+]i), potassium ion concentration ([K+]i) and membrane potential were determined by means of continuous 31P and 23Na nuclear magnetic resonance (NMR), continuous fluorescence spectroscopy and 86Rb uptake. Lactate extrusion was determined in addition with respect to pH(i) regulation. The aim of this study was a detailed picture of HS and ethanol-induced ion changes in a single cell type, because stress-induced changes in the intracellular ionic balance may be important factors for determining proliferation, stress response and apoptosis. HS lowered the pH(i) from 7.38 +/- 0.04 to about 7.05 +/- 0.04. [Na+]i decreased during HS to 50% of the control and recovered to normal level 95 min after HS treatment. During HS, [K+]i remained constant but increased after HS. The membrane potential hyperpolarized from -83 mV to -125 mV and returned to initial values during HS treatment. Lactate extrusion increased 3-fold after HS. Ethanol (1.2 M) lowered the pH(i) from pH 7.38 +/- 0.04 to pH 7.0 +/- 0.04, but in contrast to heat strongly increased [Na]i. It hyperpolarized the membrane potential from -83 to -125 mV. Ethanol also increased lactate extrusion similar to HS. Also in contrast to the effect of HS, the potassium concentration decreased during ethanol treatment. The Na(+)-H+ exchanger monensin was used to overcome the apparent inhibition of the cellular Na(+)-H+ exchanger by HS. At normal pH(e) (7.4) monensin increased [Na+]i and pH(i) considerably. A subsequent HS reduced [Na+]i only minimally. Acidification of the cells by low pH(e) (6.2) prior to HS did not abolish the HS-induced drop of pH(i), indicating that the Na(+)-H+ exchanger was also inhibited at low pH(i). At low pH(e), monensin transports H+ into the cell. A subsequent HS decreased pH(i) only little, showing the importance of inhibition of the Na(+)-H+ exchanger for the HS-induced pH(i) decrease. 100 microM amiloride reduced pH(i) and [Na+]i in a similar way as HS, but did not change pH(i) and [Na+]i much during a HS. These results indicate that some of the HS-induced ionic changes are mediated by inhibition of the Na(+)-H+ exchanger, activation of Na(+)-K(+)-ATPase and changes of membrane conductance for ions.

Quality-of-life measures: hospital interview versus home questionnaire.

Measures adapted from social survey research were used to assess the quality of life of 33 end-stage renal disease (ESRD) patients in a 2-week test-retest design that varied both location and format of administration (hospital interview vs. home self-administered questionnaire). The measures were found to have substantial consistency over time, location, and format. These results indicate that quality of life is a stable construct and support the usefulness of questionnaire quality-of-life measures for evaluating medical interventions.

Patients' perceived control over their health care: an outcome assessment of their psychological adjustment to renal failure.

Previous research has sometimes produced conflicting results regarding patients' psychological adjustment to end-stage renal disease (ESRD). It is generally accepted that treatment outcomes vary across treatment modality, with successful transplant patients reporting a higher subjective quality of life than patients on center hemodialysis. Hemodialysis and transplantation therapies vary in many ways, including the intrusiveness of treatment on all aspects of the patient's life. In the present study, 65 individuals being treated for ESRD with center hemodialysis or a renal transplant were assessed for health locus of control, for generalized control over 11 life dimensions, and for beliefs about control over specific aspects of treatment for ESRD. The study also included indicators of psychological adjustment. The results indicated that control over life dimensions, which includes control over illness, is a significant factor in psychological adjustment. Beliefs that one can comply specifically with diet and fluid restrictions were related to treatment outcome. These data suggest that interventions designed to increase patients' perception of control are likely to have a positive impact on the qualitative aspect of treatment.

Subjective quality of life measures for evaluating medical intervention.

Medical interventions are usually evaluated in terms of mortality and morbidity data, but there is recent interest in going beyond medical data to assess the impact of the therapy on the objective and subjective quality of the patient's life. Objective quality of life measures such as employment and functional status are relatively straightforward, but measuring subjective quality of life is a more complex task. This article reviews psychometric issues relevant to using subjective quality of life scales developed by Bradburn and by Campbell, Converse, and Rodgers for research with patient populations. The evidence indicates that these relatively brief scales assess both affective and cognitive aspects of subjective quality of life, that they are measuring something more stable than mood but less enduring than personality, and that they can be as sensitive as physiological measures in distinguishing among treatment groups. It is concluded that these scales offer a useful complement to more objective measures of patient status for research evaluating medical interventions.

Molar fracture resistance after adhesive restoration with ceramic inlays or resin-based composites.

PURPOSE: To determine the fracture resistance of teeth, following treatment with various types of adhesive restorations. MATERIALS AND METHODS: 5 0 caries-free, extracted human molars were randomly divided into five groups consisting of 10 molars each. MOD cavities were prepared in 40 molars with a width in the facio-lingual direction of 50% of the intercuspal distances. The cavities were filled with the following materials: Cerec or IPS Empress ceramic inlays, Arabesk or Charisma F resin-based composite (RBC) restorations. The control group consisted of 10 sound, non-restored molars. All 50 teeth were loaded occlusally until fracture using a tensile testing machine. The statistical analysis included ANOVA, Kolmogorov-Smimov-test, Scheffé test, and boxplots. RESULTS: There was no significant difference (P > 0.05) between the mean values of the sound teeth (2,102 N) and the teeth with the Cerec ceramic inlays (2,139 N). However, both groups demonstrated a significant difference (P < 0.05) when compared with the teeth with IPS Empress ceramic inlays (1,459 N) and Arabesk RBC restorations (1459 N). No significant differences were found between the last two groups. Molars restored with Charisma F composite restorations (1,562 N) revealed no significant difference when compared with all other groups including controls (P > 0.05). A stabilization of molars is possible by means of an adhesive restoration in the form of an "internal splinting" regardless of the restorative material used.

[Styloid process: radiograph and craniomandibular dysfunction (CMD)]. / Processus styloideus: Röntgenbild und cranio-mandibuläre Dysfunktion (CMD).

The aim of the study was to investigate the suitability of orthopantomograms for measuring the length of the styloid process (SP), and to determine the frequency of elongated SP in patients with craniomandibular dysfunction (CMD). For 350 patients, two ortho-pantomograms were available, produced by a SIEMENS Orthophos 5 using programs P1 and P6, respectively, plus a craniomandibular function index. The SP length measurements from the orthopantomograms and the palpation findings were correlated. In 34,7% of the 700 orthopantomograms the SP was measurable. The mean length was determined to be 29.1 mm in OPT1 films on both sides. In the OPT6 films the length values were 30.1 mm on the right, and 30.4 mm on the left side. In CMD patients there was no evidence of the SP causing the complaints. Two conclusions can be made: For epidemiologic studies on the length of the styloid process, the orthopantomogram is of limited use. In CMD patients the elongated styloid process is of negligible importance as a cause of complaints.

Detection of low HCV viraemia by repeated HCV RNA testing predicts treatment failure to triple therapy with telaprevir.

BACKGROUND: Early on-treatment virological response is one of the most important predictors for sustained virological response (SVR) to treatment of chronic hepatitis C virus (HCV) genotype 1 infection with triple therapy including HCV protease inhibitors (PI). Treatment duration (24 vs. 48 weeks) is based on HCV RNA results at weeks 4 and 12 of PI therapy when HCV RNA must be 'undetectable' to allow shorter therapy. AIM: To analyse the reliability of HCV RNA measurements at key decision time points (weeks 4 and 12) and the predictive value of concordant or discordant assay results for SVR. METHODS: Weeks 4 and 12 samples of patients receiving telaprevir-containing triple therapy were initially tested with the AmpliPrep/COBAS-TaqMan_HCV-Test-v1.0 (limit of detection; LOD = 15IU/mL) and retested with the AmpliPrep/COBAS-TaqMan_HCV-Test-v2.0 (LOD = 15IU/mL) and the High_Pure/COBAS-TaqMan_HCV-Test-v2.0 (LOD = 20IU/mL). RESULTS: Concordance among the three test results in classifying samples as HCV RNA 'undetectable' or 'detectable' was only 55% at week 4, but 85% at week 12. Retesting of 'undetectable' week 4 samples with the respective other assays revealed positive HCV RNA results in 32-50%. In 30%, HCV RNA was 'undetectable' by all three tests at week 4 and all of these patients achieved SVR. In contrast, treatment failure occurred in 62% of patients with at least one 'detectable' result, including cases with one or two other 'undetectable' tests at week 4. CONCLUSIONS: A single 'undetectable' HCV RNA result at week 4 is not always associated with achieving SVR. Repeated testing in difficult-to-treat patients may identify those at risk for treatment failure.