Fourth-generation assays for the simultaneous detection of human immunodeficiency virus (HIV) antigenSince the first enzyme immunoassays (EIA) for blood donor screening and laboratory diagnosis of human immunodeficiency virus (HIV) infection were licensed over 15 years ago, the quality of these tests has been continuously improved by the use of recombinant antigens and synthetic peptides (second test generation) and the sandwich EIA technology (third test generation) (10, 36). There is however a residual risk for false-negative results. The potential causes include the diagnostic window in the preseroconversion phase, genetic variability, atypical seroconversions, a delayed or absent immune re-

Early detection of hepatitis C virus (HCV) is an important step in preventing progression to cirrhosis and hepatocellular carcinoma. Serologic assays for anti-hepatitis C (anti-HCV) antibody are valuable first-line tests in the screening and diagnosis of HCV infection. The aim of this multicenter study was to compare the Elecsys(®) Anti-HCV assay with alternative CE-marked Anti-HCV antibody assays against a range of samples that included 1,138 blood donors, 3,553 unselected routine daily specimens, and 46 pre-selected seroconversion panels. Specificity of the Elecsys Anti-HCV assay was 99.5% with blood donor samples and 99.4% with routine clinical specimens. These were similar to those obtained with the Prism(®) Anti-HCV, Architect(®) Anti-HCV assay, ADVIA(®) Centaur Anti-HCV assay and Vitros(®) Eci aHCV assays. Seroconversion sensitivity for the Elecsys Anti-HCV assay was similar to that of the Architect Anti-HCV, AxSYM HCV version 3.0, ADVIA Centaur Anti-HCV, and Vitros Eci aHCV assays. In fact, seroconversion testing on 46 commercially available panels showed that the difference in first detecting a positive blood sample was less than one day between assays (not statistically significant). The Elecsys Anti-HCV assay as well as the Architect, Prism, and Vitros Anti-HCV immunoassays revealed a seroconversion sensitivity of 100%, whereas the ADVIA Centaur HCV immunoassay showed a sensitivity of only 97.5% (39/40). Overall, the performance of the Elecsys Anti-HCV assay was similar to the performances of the comparator CE-marked Anti-HCV antibody assays.

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Background: Hypolactasia and lactose intolerance are common conditions worldwide. Hypolactasia seems to be strongly correlated with genotype C/C of the genetic variant C→T−13910 upstream of the lactase phlorizin hydrolase (LPH) gene. We developed a rapid genotyping assay for LPH C→T−13910 and investigated the relationship of positive lactose breath hydrogen test (LBHT) results suggesting lactose intolerance with LPH C→T−13910 genotype. Methods: Using automated DNA purification on the MagNA Pure LC and real-time PCR on the LightCycler, we examined samples from 220 individuals to estimate genotype frequencies; we then determined LPH C→T−13910 genotype in samples from 54 Caucasian patients with a positive LBHT result and symptoms of lactose intolerance. Results: Genotyping of 220 individuals revealed frequencies of 21.4%, 41.8%, and 36.8% for genotypes C/C, C/T, and T/T. Of the patients with positive LBHT results, only 50% had the C/C genotype suggestive of primary adult hypolactasia in our study population. The other patients had various degrees of secondary hypolactasia or symptoms of lactose intolerance. Patients with C/C genotype had a mean (SD) peak H2 increase in the LBHT [108 (58) ppm] that was significantly higher than in patients with the C/T [65 (54) ppm] and T/T [44 (34) ppm] genotypes. Conclusions: The new real-time PCR assay provides a rapid, labor-saving means for the genotyping of LPH C→T−13910. Use of the assay may assist in differentiating patients with primary hypolactasia from those with secondary hypolactasia and lactose intolerance, who may need further clinical examinations to diagnose their underlying primary diseases.