A common variant of the LHb-sub-unit has a variable prevalence in various ethnic groups. The physiological consequences of the presence of this mutated LH are some borderline alterations in pituitary-gonadal function, including a higher risk for the development of more aggressive forms of prostate carcinoma in males. The objective was firstly, to ascertain the frequency of the occurrence of the LHb-variant in both sexes in a selected region in the Czech Republic and secondly, to evaluate the efficiency of the discrimination between „wild type“ homozygotes, heterozygotes and LHb-variant homozygotes using the methods described below. The sample was a randomly selected group of the normal population and consisted of 82 males and 175 females from 14 to 72 years of age. Variant LH was determined by an immunofluorimetric method for LH estimation using two antisera with different specificity. Cluster analysis used for the analysis of homogeneity of the data revealed the clustering in both types of LH in females when plotted against age. The age dependence of both types of LH was more marked in women. In men, a higher correlation with age was observed in LH-variant carriers, however, it was not significant due to the low number of samples. The frequency of the occurrence of variant LH in males and females in the western region of the Czech Republic was 12.2% and 20.6%, respectively. These values were within the range of European prevalence and did not differ significantly between the sexes. Discriminant analysis was used for statistical evaluation of the discrimination between „wild type“ homozygotes and carriers of the LHb-variant allele. Excellent (100%) discrimination between the „wild type“ homozygotes and the carriers of the LHb-variant allele was found using the ratio (LH determined by LH-variant non-specific antiserum)/(LH-variant specific antiserum) as the discriminator.

        Key words: LH-variant, LH-prevalence, LHb-sub-unit, DELFIA, monoclonal antibody.