Demographic and analytic factors affecting the normal range of serum enzyme activities.
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.
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
D004798:Enzymes; D007770:L-Lactate Dehydrogenase; D006884:Hydroxybutyrate Dehydrogenase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D003402:Creatine Kinase; D009708:Nucleotidases; D000469:Alkaline Phosphatase