title: Demographic and analytic factors affecting the normal range of serum enzyme activities.
abstract: 1. The effect of demographic variables such as age, sex, body weight, social class and blood pressure upon the activity of serum enzymes in healthy humans is reviewed. A system developed by the author and his colleagues, which automatically adjusts the results of enzyme activity measurements to allow for demographic influences, is described. This allows derivation of a "demographically corrected" normal range; for most enzymes this range is much narrower than that provided by the conventional mean +/- 2 SD approach. 2. The influence of precision and analytical factors upon the normal range for serum enzymes is discussed. Data from a British national quality-control survey reveal a depressing picture of interlaboratory precision for commonly determined enzyme estimations. Examples are given (serum aspartate aminotransferase and guanase) which illustrate the influence that precision of a method may have on the normal range for that enzyme.
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000410:Alanine Transaminase / Q000097:blood; D000469:Alkaline Phosphatase / Q000097:blood; D001219:Aspartate Aminotransferases / Q000097:blood; D001322:Autoanalysis; D002648:Child; D002675:Child, Preschool; D003402:Creatine Kinase / Q000097:blood; D003710:Demography; D004798:Enzymes / Q000097:blood*; D005260:Female; D006801:Humans; D006884:Hydroxybutyrate Dehydrogenase / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008297:Male; D008722:Methods; D008875:Middle Aged; D009708:Nucleotidases / Q000097:blood; D011786:Quality Control; D012044:Regression Analysis; D012737:Sex Factors
chemical_list: D004798:Enzymes; D007770:L-Lactate Dehydrogenase; D006884:Hydroxybutyrate Dehydrogenase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D003402:Creatine Kinase; D009708:Nucleotidases; D000469:Alkaline Phosphatase