Seroprevalence of Measles Antibodies in the Population of the Olomouc Region, Czech Republic-Comparison of the Results of Four Laboratories.

OBJECTIVES: Although the incidence of measles has decreased globally since the introduction of regular vaccination, its frequency has increased again in recent years. The study is focused on data from the Olomouc Region in the Czech Republic analyzed in four laboratories. The obtained results were compared with already published data. METHODS: The data were provided by individual laboratories in an anonymized form-age at the time of the examination, sex, and result of test. Samples were collected between June 2018 and September 2019 and evaluated on the scale positive-borderline-negative. RESULTS: A total of 7962 sera samples were evaluated using three different methods-two types of ELISA tests and CLIA. Positive result was issued in a total of 62.6 percent of samples, but the results of individual laboratories varied widely from 55.5 to 70.8 percent. However, the same trend with the highest levels of antibodies in people born before beginning of vaccination was observed. CONCLUSIONS: Data show significantly different results depending on the individual laboratories and the detection kits used. The underestimation of the proportion of positive results can cause problems in selecting individuals for revaccination with a live vaccine, which may fail in weakly positive individuals.

Urease-immobilized magnetic microparticles in urine sample preparation for metabolomic analysis by gas chromatography-mass spectrometry.

Urea, as an end product of protein metabolism and an abundant polar compound, significantly complicates the metabolomic analysis of urine by GC-MS. We developed a sample preparation method removing urea from urine samples prior the GC-MS analysis. The method based on urease immobilized on magnetic microparticles was compared with the others that are conventionally used (liquid-liquid extraction, free urease protocol), and samples without any treatment. To study the impact of sample preparation approaches on the quality of analytical data, we employed comprehensive metabolomic analysis (using both GC-MS and LC-MS/MS platforms) of standard material based on human urine. Multivariate statistical analysis has shown that immobilized urease treatment provides similar results to a free urease approach. However, significant alterations in the profiles of metabolites were observed in the samples without any treatment and after the extraction. Compared to other approaches that were tested, the immobilization of urease on microparticles reduces both the number of artifacts and the variability of the metabolites (average CV of extraction 19.7%, no treatment 11.4%, free urease 5.0%, and immobilized urease 2.5%). The method that was developed was applied in a GC-MS metabolomic experiment of glutaric aciduria type I, where both known diagnostically important biomarkers and unknowns, as the most discriminating compounds, were found.