Primary cytomegalovirus (CMV) infection in pregnancy: Diagnostic value of CMV PCR in saliva compared to urine at birth.

BACKGROUND: Due to its ease of collection saliva was recently recommended as the preferred specimen, not only for screening, but also for diagnosis of congenital cytomegalovirus (CMV) infection. OBJECTIVE: To compare the diagnostic performance of saliva PCR to urine PCR in infants born to mothers with primary CMV infection during pregnancy. STUDY DESIGN: We retrospectively analyzed available data of infants tested for CMV DNA in urine and saliva at birth. PCR was performed with RealStar® CMV-PCR Kit 1.0 (altona Diagnostics). Infectious virus was detected in urine by rapid culture. RESULTS: A total of 133 newborns were eligible for final analysis. Saliva swabs and urine were collected at birth with a time interval of 0-8 days (median 0; IQR 0-1). In 55% of newborns, cord blood was also tested. The overall concordance of saliva and urine PCR was 91% (27 positive, 94 negative). In 12 cases with discordant findings the discrepancy was due to false-negative (n = 2) or false-positive (n = 10) PCR results in saliva. Compared to urine, PCR in saliva showed a positive predictive value of 73%. Viral load in saliva was significantly lower (p < 0.0001; Mann-Whitney test) in the 10 false-positive cases than in the 27 cases with concordantly positive results. CONCLUSIONS: Positive CMV PCR results in saliva, especially low positive, have to be confirmed by urine testing. In our opinion detection of CMV by PCR in neonatal urine remains the gold standard for diagnosing congenital CMV infection in infants of mothers with primary infection in pregnancy.

Performance of the Elecsys Rubella IgG assay in the diagnostic laboratory setting for assessment of immune status.

Rubella in early pregnancy bears a high risk for congenital defects (e.g., cataracts, hearing loss, and heart disease) and for long-term sequelae in the newborn. Despite implementation of vaccination programs in many regions, the threat of devastating consequences from congenital rubella virus infection remains and careful screening of maternal immune status before and during pregnancy helps to reduce the risk. This study compared the performance of the Elecsys Rubella IgG assay with that of other assays routinely used for screening. Samples from 1,090 women undergoing routine antenatal care were tested using the Elecsys and Enzygnost Rubella IgG assays and the hemagglutination inhibition test. Samples with hemagglutination inhibition titers of <32 (n = 148) were additionally tested using the Vidas, AxSYM, Liaison, and Architect Rubella IgG assays. Agreement of qualitative results from the Elecsys, Enzygnost, and hemagglutination inhibition assays was good in all samples. All assays showed 100.0% specificity. In samples with hemagglutination inhibition titers of <32, the Elecsys, AxSYM, and Enzygnost assays showed higher sensitivity (>90.0%) than the other immunoassays (78.6 to 82.4%). The Elecsys assay reported significantly higher rubella virus IgG levels than the other immunoassays across the whole set of 1,090 samples, with the largest bias and deviation from limits of agreement in Bland-Altman analysis. In conclusion, the Elecsys assay is highly sensitive and specific with regard to qualitative results and suitable for routine automated screening. However, given the considerable variation between quantitative results from different immunoassays, testing methods should be documented and the same assay used throughout an individual's antenatal follow-up wherever possible.

The value of CMV IgG avidity and immunoblot for timing the onset of primary CMV infection in pregnancy.

BACKGROUND: Primary CMV infections in pregnancy are usually asymptomatic and only detected by serology. Estimating the onset of infection is a major diagnostic goal, since primary infections around conception and in early gestation hold a higher risk for congenital disease than those in later pregnancy. OBJECTIVES: To assess the ability of serological supplementary CMV assays to date the onset of primary infection. STUDY DESIGN: From our routine diagnosis we identified 61 pregnant women (n=188 serum samples) with precisely determined onset of CMV primary infection either by IgG seroconversion (n=24) or by significant IgG antibody rise (n=37). One hundred and forty-seven sera were investigated using the VIDAS(®) CMV IgG avidity EIA (BioMèrieux) and 83 sera using the recomBlot CMV IgG with avidity (Mikrogen). RESULTS: Both assays proofed to be reliable in terms of timing the onset of CMV primary infection. An avidity index (AI) in the VIDAS avidity EIA of <40% indicated primary infection within the last 20 weeks (positive predictive value 93.4%; 99/106), whereas an intermediate AI excluded primary infection within the last 12 weeks (negative predictive value 88.2%; 15/17). The recomBlot showed high reliability (PPV 96.9%; 31/33) for timing the onset of infection within the last 14 weeks. Avidity testing by blot however could not be interpreted in 11 of 47 sera (23.4%). CONCLUSION: For timing the onset of infection (before or in early pregnancy) CMV avidity testing is most helpful if carried out within the first trimester up to the beginning of second trimester.

Use of cytomegalovirus hyperimmunoglobulin for prevention of congenital cytomegalovirus disease: a retrospective analysis.

AIMS: The aim of this study was to investigate the current prenatal "off-label use" of cytomegalovirus hyperimmunoglobulin (CMV-HIG) in the prevention and treatment of congenital CMV (cCMV) infection, including the long-term outcome of the children. METHODS: This retrospective observational study comprised mothers and their children, born between January 1, 2006, and October 30, 2010. Prenatal CMV-HIG was administered after diagnosis of primary CMV infection of the mother. Clinical and virological data were collected from maternal and pediatric medical and laboratory reports. Follow-up was 12-36 months after birth. RESULTS: Forty-two women and 43 children met the study criteria. In total, 40 mothers and six unborn infants received 115 doses of CMV-HIG. The treatment group (TG; CMV-DNA polymerase chain reaction-positive amniotic fluid) included four mothers; the multinomial group (MG; CMV-positive mother and unknown CMV status of fetus) included 38 mothers (39 infants). For the four unborn infants in TG, CMV-HIG was administered either intraumbilically or into the amniotic fluid; three of the four mothers received intravenous CMV-HIG. Three children in TG remained CMV-positive and were asymptomatic at birth and during follow-up. One infant in TG had symptomatic cCMV infection in utero, at birth, and during follow-up. In MG, 37 of 38 women received intravenous CMV-HIG and two of 39 infants received CMV-HIG in utero. In total, 9 (23.1%) of 39 children in MG were positive for cCMV (including a terminated pregnancy). All eight instances of cCMV infection at birth in MG were asymptomatic at birth and during follow-up. The fetus from the terminated pregnancy showed no sonographic symptoms of cCMV infection. No severe side effect occurred in 115 CMV-HIG applications. CONCLUSION: CMV-HIG was well tolerated. Compared with published untreated mother-child pairs, we observed a trend toward a smaller risk for intrauterine CMV transmission following CMV-HIG application. Signs of prenatal cCMV disease were not reversed after CMV-HIG.

Cytomegalovirus (CMV) seroprevalence in pregnant women, bone marrow donors and adolescents in Germany, 1996-2010.

In Germany, studies on the IgG seroprevalence in pregnancy and in women of childbearing age are rare. Therefore, we retrospectively evaluated the CMV IgG seropositive rate in 40,324 pregnant women as well as in 31,093 female and male bone marrow donors over 15 consecutive years (1996-2010). Furthermore, the result of a study conducted in 1999 investigating 1,305 healthy adolescents with known ethnicity was included. The overall CMV IgG seroprevalence in pregnant women (15-50 years) was 42.3%. Age-dependent analysis revealed a significantly higher seropositive rate (55.6%) in young women (15-25 years) than in those aged 26-40 years (37-42%) and in women older than 40 years (48.3%). Over the study period of 15 years, the rate of seroprevalence in pregnant women declined significantly (χ(2) test < 0.01) from 44.3% in the first interval period (1996-2000), to 42.8% (2001-2005) and to 40.9% (2006-2010). The most influencing factor on CMV seropositivity appeared to be the socioeconomic status (SES), which we characterized by type of health insurance: Seroprevalence in women with low, middle and upper SES was 91.8, 46.9 and 33.7%, respectively. Female bone marrow donors of childbearing age (15-45 years) showed a significantly higher seropositive rate of 36.5% than age-matched male donors (28.6%). In adolescents aged 13-16 years, no gender-specific differences were recognized. Concerning ethnicity, youngsters with German descent had a significantly lower seroprevalence (29.9%) than those with non-German descent (67.4%).

Development and evaluation of an automatable focus reduction neutralisation test for the detection of measles virus antibodies using imaging analysis.

A plaque reduction neutralisation test (PRNT) is still regarded as the gold standard for the investigation of anti-measles immunity. In this study, an alternative simplified automatable focus reduction neutralisation test (AFRNT) based on the classical PRNT was developed. The AFRNT uses the conventional Edmonston strain of measles, immunoperoxidase staining with monoclonal antibodies, and automated plaque counts performed with AID ViruSpot software. The assay is performed in 96-well plates, requires 2 days, and is fully automatable. The AFRNT was evaluated in comparison with PRNT and Enzygnost anti-measles enzyme immunoassay (EIA). A total of 130 samples, which included two available WHO international anti-measles standards, sera from 90 patients, and 38 different lots of immunoglobulin products, were tested. Overall, good agreement was observed between EIA and both neutralisation tests; however, the EIA values for the immunoglobulin products and international standards were slightly but significantly higher than those of the neutralisation tests. The Bland-Altman analysis showed excellent agreement between AFRNT and PRNT. AFRNT is a fully automatable high-throughput neutralisation assay, which can be performed with measles and other types of viruses, including wild-type strains. It is perfectly suited for epidemiological and vaccine studies.

Intrauterine transmission and clinical outcome of 248 pregnancies with primary cytomegalovirus infection in relation to gestational age.

BACKGROUND: The risk of intrauterine cytomegalovirus (CMV) infection and disease in the fetus or newborn largely depends on time of primary maternal infection during pregnancy. OBJECTIVES: Prospective cohort study of pregnancy outcome in relation to gestational age at primary maternal CMV infection. STUDY DESIGN: In a total of 248 pregnancies with primary infection the onset of infection was determined by IgG seroconversion, IgG avidity and/or onset of clinical symptoms. Congenital infection was diagnosed by CMV detection in amniotic fluid, fetal tissue or urine of the neonate in the first 2 weeks of life. Clinical symptoms were retrieved from ultrasound and medical records. RESULTS: The intrauterine transmission rates following primary CMV infection in the pre- and periconceptional period were 16.7% (4/24) and 34.5% (10/29), respectively. For the first, second and third trimester of pregnancy transmission rates were 30.1% (25/83), 38.2% (29/76) and 72.2% (26/36), respectively. The rate of symptomatically infected fetuses or newborns at birth was 22.8% for any symptoms and 10.3% for severe manifestations. No symptoms were observed in infected newborns of mothers with primary infection in the preconceptional period and in the third trimester. CONCLUSIONS: The risk of intrauterine transmission following primary maternal infection in the third trimester is high, but the risk of neonatal disease is low. The highest risk of severe symptoms in the fetus and newborn exists around conception and in the first trimester of pregnancy.

Diagnosis of recent primary rubella virus infections: significance of glycoprotein-based IgM serology, IgG avidity and immunoblot analysis.

Reliable serodiagnosis of rubella virus (RV) infections requires discrimination of specific IgM induced by primary rubella from persistent, reactivated or non-specific IgM reactivity. Sera from 130 pregnant women with recent or past RV infection/vaccination, persistent IgM or negative rubella serology, 26 patients with other acute infections and 5 patients with rheumatoid factor-positivity were analyzed for RV-specific IgM by ELISA coated with whole-virus lysate or native glycoprotein, followed by determination of IgG avidity and E2-specific IgG using lysate-coated ELISA and non-reducing immunoblot. Compared to a reference µ-capture IgM ELISA, the sensitivity for diagnosing recent rubella infection/vaccination was 90.0% and 100% for the lysate-based and glycoprotein-based IgM ELISA, respectively. With respect to women with past RV infections or negative histories of RV infection/vaccination, both assays were 97.5-100% specific, whereas for patients with other acute infections the glycoprotein substrate provided a specificity of 92.3% compared to only 80.8% using whole-virus antigen. Analyzing anti-RV IgG avidity and anti-E2 IgG reactivity allowed the time point of primary infection to be determined unambiguously in >86% of samples. In conclusion, using RV glycoprotein antigen improves the specificity of indirect IgM ELISA. In cases of RV-specific IgM reactivity, recent primary rubella infection can be confirmed or excluded efficiently by specific IgG avidity and immunoblot analysis.

Immunity status of adults and children against poliomyelitis virus type 1 strains CHAT and Sabin (LSc-2ab) in Germany.

BACKGROUND: In October 2007, the working group CEN/TC 216 of the European Committee for standardisation suggested that the Sabin oral poliovirus vaccine type 1 strain (LSc-2ab) presently used for virucidal tests should be replaced by another attenuated vaccine poliovirus type 1 strain, CHAT. Both strains were historically used as oral vaccines, but the Sabin type 1 strain was acknowledged to be more attenuated. In Germany, vaccination against poliomyelitis was introduced in 1962 using the oral polio vaccine (OPV) containing Sabin strain LSc-2ab. The vaccination schedule was changed from OPV to an inactivated polio vaccine (IPV) containing wild polio virus type 1 strain Mahoney in 1998. In the present study, we assessed potential differences in neutralising antibody titres to Sabin and CHAT in persons with a history of either OPV, IPV, or OPV with IPV booster. METHODS: Neutralisation poliovirus antibodies against CHAT and Sabin 1 were measured in sera of 41 adults vaccinated with OPV. Additionally, sera from 28 children less than 10 years of age and immunised with IPV only were analysed. The neutralisation assay against poliovirus was performed according to WHO guidelines. RESULTS: The neutralisation activity against CHAT in adults with OPV vaccination history was significantly lower than against Sabin poliovirus type 1 strains (Wilcoxon signed-rank test P < 0.025). In eight sera, the antibody titres measured against CHAT were less than 8, although the titre against Sabin 1 varied between 8 and 64. Following IPV booster, anti-CHAT antibodies increased rapidly in sera of CHAT-negative adults with OPV history. Sera from children with IPV history neutralised CHAT and Sabin 1 strains equally. CONCLUSION: The lack of neutralising antibodies against the CHAT strain in persons vaccinated with OPV might be associated with an increased risk of reinfection with the CHAT polio virus type 1, and this implies a putative risk of transmission of the virus to polio-free communities. We strongly suggest that laboratory workers who were immunised with OPV receive a booster vaccination with IPV before handling CHAT in the laboratory.

Risk of fetal hydrops and non-hydropic late intrauterine fetal death after gestational parvovirus B19 infection.

BACKGROUND: Risk assessment of parvovirus B19 (B19)-associated fetal complications following gestational B19 infection remains controversial. OBJECTIVES: To determine the risk of fetal hydrops or non-hydropic late intrauterine fetal death following acute maternal B19 infection at defined gestational weeks. STUDY DESIGN: Observational cohort study of pregnant women with serologic evidence of acute B19 infection. If available, fetal or neonatal tissue samples from cases complicated by fetal loss or hydrops were investigated for the presence of B19 DNA by polymerase chain reaction (PCR) and/or in situ hybridization (ISH). RESULTS: Of 236 women with known pregnancy outcome, 228 had a live birth and 8 a fetal loss. The observed rate of fetal hydrops for all pregnant women was 4.2% (10/236) (95% confidence interval [CI], 2.1-7.7) and 10.6% (10/94) (95% CI, 5.2-18.7) for those infected between 9 and 20 weeks gestation. Tissue samples from 8 hydrops cases were investigated by PCR or ISH and all were B19 DNA positive. Fetal death occurring during or after gestational week 22 was only observed in one case which was associated with B19-derived fetal hydrops. CONCLUSIONS: Our findings demonstrate that although adverse fetal outcome is a rare complication of gestational B19 infection, a relevant risk of fetal hydrops exists particularly for women infected between 9 and 20 weeks' gestation. Cases of B19-derived non-hydropic late intrauterine fetal death were not observed in the present study.

No detection of human bocavirus in amniotic fluid samples from fetuses with hydrops or isolated effusions.

BACKGROUND: Human bocavirus (HBoV) is a recently identified parvovirus associated with respiratory disease in infants. Animal bocaviruses have been shown to cause intrauterine infection, fetal anasarca and abortion in late gestation. OBJECTIVES: To investigate whether HBoV infection is associated with fetal hydrops, fetal anemia or isolated fetal effusions. STUDY DESIGN: We determined the prevalence of HBoV and parvovirus B19 (B19) DNA in amniotic fluid samples from fetuses with hydrops, anemia or isolated effusions using different real-time PCR protocols, and the HBoV IgG and IgM positivity rate in pregnant women with fetal hydrops or normal ultrasound findings by a non-commercial virus-like particle-based enzyme immunoassay. RESULTS: None of 87 amniotic fluid samples tested was HBoV DNA positive. Twelve of 60 fetuses with hydrops or anemia were found B19 DNA positive. Anti-HBoV IgG antibodies were detected in 100% (19/19) and 94% (47/50) of serum samples from pregnant women with fetal hydrops and normal ultrasound findings, respectively. All serum samples were found negative for anti-HBoV IgM. CONCLUSION: We suggest that HBoV is not a common cause of fetal hydrops, anemia or isolated effusions. This has to be confirmed by further studies of proven gestational HBoV infection.

Evaluation of a new ELISA for the detection of specific IgG to the Epstein-Barr nuclear antigen 1 (EBNA-1).

Diagnosis of acute primary Epstein-Barr Virus (EBV) infection is predominantly performed by serology. Detection of specific antibodies to defined EBV antigens is considered state of the art. Antibodies to EBNA-1 are not produced early in primary infection and a positive EBNA-1 serology is a sign of past infection. Therefore EBNA-1 serology plays a crucial role for EBV routine diagnosis. In the present study the quantitative EBV EBNA-1-IgG-ELISA PKS medac was evaluated regarding its suitability for routine diagnosis. Using clinically and diagnostically defined serum samples (141 from seronegative, 111 from acute infected, and 52 from individuals with past infection) as well as 100 sera from healthy blood donors the diagnostic performance of the assay was investigated. Furthermore, precision, performance of the single-point quantitation (SPQ), and suitability of the assay for automation were evaluated. Compared to the pre-definition of the serum panel a sensitivity of 100% and a specificity of 99.6% was found. The measurement of the blood donor sera resulted in an anti-EBNA-1 IgG prevalence of 93% and an agreement of 99% with the results of a commercial ELISA used as reference. Regarding intra-assay variation, interassay variation (performed manually and automatically), and person-to-person variation a coefficient of variation < 10% was found with reactive samples. A good dilution linearity (r2 = 0.961), an excellent correlation of SPQ vs. the calibration curve (r2 = 0.997), and between the results of manually vs. automatically performed test runs (r2 > 0.995) was found. The evaluation has shown that the assay meets the demands of routine diagnosis very well.

Improvement of cytomegalovirus avidity testing by adjusting the concentration of CMV-specific IgG in test samples.

BACKGROUND: Human cytomegalovirus (CMV) is the most common cause of viral intrauterine infection. Primary CMV infection in early pregnancy bears a high risk of fetal damage. Accurate measurement of CMV-specific IgG avidity may help to improve the serodiagnosis of CMV-infected women by determining the time of infection and fetal outcome. OBJECTIVES: To study the performance of the CMV avidity assay with the fully automated Vidas analyzer (bioMérieux) as a function of the concentration of CMV-specific IgG present in the serum sample. STUDY DESIGN: Eighty-two serum samples were investigated from 3 clinical scenarios: 18 individuals with sera negative for CMV-specific IgG and IgM (control group), 20 pregnant women (44 samples) containing CMV-specific IgG- and IgM-antibodies suggesting acute or recent primary infection and 20 patients with evidence of past infection (CMV-IgG positive and CMV-IgM negative). RESULTS: In the group with presumed acute or recent primary infection 12 of 44 sera had CMV-specific IgG values above 100 arbitrary units (AU, bioMérieux)/ml and in these cases an increase in AI was measurable upon dilution of the serum sample. In two cases, AI's were shifted towards or above the cut-off value of AI>or=0.8, indicative of past infection. Dilution of sera which were CMV-specific IgM positive and had specific IgG concentrations of

Seroreactivity to and avidity for recombinant antigens in toxoplasmosis.

To improve serodiagnostic methods for the diagnosis of acute toxoplasmosis during pregnancy, a new test system has been developed and evaluated based on the use of recombinant antigens. Five recombinant Toxoplasma gondii antigens (ROP1, MAG1, SAG1, GRA7, and GRA8) were cloned in Escherichia coli, purified, and applied directly onto nitrocellulose membranes in a line assay (recomLine Toxoplasma). A panel of 102 sera from 25 pregnant women with supposed recent toxoplasmosis and from two symptomatic children was compared to a panel of 71 sera from individuals with past infection. Both panels were analyzed using a recombinant line assay for immunoglobulin G (IgG), IgM, and IgA antibodies and a reference enzyme-linked immunosorbent assay. Within the IgM-positive samples, antibodies against ROP1 were predominant regardless of the infection state. In IgG analysis a characteristic antibody pattern was found for very recent infections. This pattern changed to a different one during the time course of infection: antibodies against GRA7 and GRA8 were characteristic for very early IgG, whereas antibodies against SAG1 and MAG1 appeared significantly later. These results were further confirmed by determination of the IgG antibody avidity for every single recombinant antigen. In the time course of infection, IgG antibodies against the early recognized antigens matured significantly earlier than those directed against the later antigens did. The IgA patterns did not give reliable information about the infection time points. The data revealed that the recombinant line assay provides valuable information on the actual state of infection, especially during the early infection time points.

Defining the timing of respiratory syncytial virus (RSV) outbreaks: an epidemiological study.

BACKGROUND: Seasonal RSV infections occur every year and affect particularly children under six months of age. Passive immunoprophylaxis with monoclonal antibody Palivizumab is recommended in the period with high risk of RSV infection. This study aims to define the period for the southern part of Germany (Stuttgart area). METHODS: Epidemiological analysis of the RSV situation in southern Germany from 1996 to 2004 and comparison of results with literature was made. The respiratory tract specimens were sent in for the detection of RSV mainly by paediatric clinics. Detection of RSV was carried out mainly by real-time RT-PCR or by ELISA "Pathfinder". RSV outbreaks were depicted as an absolute number and as a percentage of RSV diagnoses in a month. Onsets, offsets, peaks, duration and severity of RSV seasons were defined and analysed. RESULTS: An early season with strong RSV activity (early-high phase) was followed by a weaker late season (late-low phase) in a regular biennial rhythm. However, onsets, offsets and durations of outbreaks varied significantly from year to year. RSV epidemics in southern Germany were found to oscillate in an antiphase with RSV epidemics in Finland and Sweden. CONCLUSION: The long-term regular biennial rhythm allows predicting whether the next outbreak will be late or early and whether RSV activity will be strong or weak. Not foreseeable, however, is the precise time of increase and decrease of RSV activity. Moreover, the regular seasonal pattern may be disrupted by irregular outbreaks. Thus, activity of RSV has to be monitored every year to define the period with high risk of infection.

Fetal morbidity and mortality after acute human parvovirus B19 infection in pregnancy: prospective evaluation of 1018 cases.

OBJECTIVE: To determine more precisely the incidence of fetal complications following maternal parvovirus B19 infection at various gestational ages. METHODS: An observational prospective study of 1018 pregnant women whose acute B19 infection was serologically confirmed in our laboratory. RESULTS: The observed rate of fetal death throughout pregnancy was 6.3% (64/1018) (95% confidence interval [CI]: 4.9, 8.0). The fetal death rate for those infected within the first 20 weeks of gestation (WG) was 64/579 (11.0%). Fetal death was only observed when maternal B19 infection occurred before the completed 20 WG. The observed stillbirth proportion was 0.6% (6/960). Three of six stillbirth cases presented with fetal hydrops. The overall risk of hydrops fetalis was 3.9% (40/1018) (95% CI: 2.8, 5.3). Three of 17 cases with non-severe hydrops and 13 of 23 cases with severe hydrops received intrauterine transfusion(s). The proportion of fetuses with severe hydrops that survived following fetal transfusions was 11/13 (84.6%). All of the non-transfused fetuses with severe hydrops died. CONCLUSION: Our data demonstrate a relevant B19-associated risk of fetal death, which is largely confined to maternal B19 infection in the first 20 WG. Timely intrauterine transfusion of fetuses with severe hydrops fetalis reduces the risk of fetal death. Parvovirus B19-associated stillbirth without hydropic presentation is not a common finding.

Fast detection of Noroviruses using a real-time PCR assay and automated sample preparation.

BACKGROUND: Noroviruses (NoV) have become one of the most commonly reported causative agents of large outbreaks of non-bacterial acute gastroenteritis worldwide as well as sporadic gastroenteritis in the community. Currently, reverse transcriptase polymerase chain reaction (RT-PCR) assays have been implemented in NoV diagnosis, but improvements that simplify and standardize sample preparation, amplification, and detection will be further needed. The combination of automated sample preparation and real-time PCR offers such refinements. METHODS: We have designed a new real-time RT-PCR assay on the LightCycler (LC) with SYBR Green detection and melting curve analysis (Tm) to detect NoV RNA in patient stool samples. The performance of the real-time PCR assay was compared with that obtained in parallel with a commercially available enzyme immunoassay (ELISA) for antigen detection by testing a panel of 52 stool samples. Additionally, in a collaborative study with the Baden-Wuerttemberg State Health office, Stuttgart (Germany) the real-time PCR results were blindly assessed using a previously well-established nested PCR (nPCR) as the reference method, since PCR-based techniques are now considered as the "gold standard" for NoV detection in stool specimens. RESULTS: Analysis of 52 clinical stool samples by real-time PCR yielded results that were consistent with reference nPCR results, while marked differences between the two PCR-based methods and antigen ELISA were observed. Our results indicate that PCR-based procedures are more sensitive and specific than antigen ELISA for detecting NoV in stool specimens. CONCLUSIONS: The combination of automated sample preparation and real-time PCR provided reliable diagnostic results in less time than conventional RT-PCR assays. These benefits make it a valuable tool for routine laboratory practice especially in terms of rapid and appropriate outbreak-control measures in health-care facilities and other settings.