title: Amniotic fluid alkaline phosphatase, gamma-glutamyltransferase, and 5'-nucleotidase activity from 13 to 40 weeks' gestation, and alkaline phosphatase as an index of fetal lung maturity.
abstract: Reference ranges for amniotic fluid alkaline phosphatase, gamma-glutamyltransferase, and 5-nucleotidase are described from 13 to 40 weeks' gestation. Gamma-glutamyltransferase and 5-nucleotidase activities peak early in the second trimester and then decrease to low values. Alkaline phosphatase shows a similar pattern of activity from 13 to 29 weeks' gestation, but thereafter activity increases to term; this late increase is mainly related to the heat-labile particulate form of alkaline phosphatase. Total and heat-labile alkaline phosphatase alone or expressed as a ratio with gamma-glutamyltransferase can be used with or as an alternative to lecithin/sphingomyelin ratios in the investigation of fetal lung maturity. A total alkaline phosphatase activity of 0.36 mukat/L and an alkaline phosphatase/gamma-glutamyltransferase ratio greater than 2 indicate pulmonary maturity.
mesh_terms: D000469:Alkaline Phosphatase / Q000032:analysis*; D000653:Amniotic Fluid / Q000201:enzymology*; D005260:Female; D005325:Fetal Organ Maturity; D005865:Gestational Age; D006801:Humans; D007527:Isoenzymes / Q000032:analysis; D008168:Lung / Q000196:embryology*; D009708:Nucleotidases / Q000032:analysis*; D011247:Pregnancy; D005723:gamma-Glutamyltransferase / Q000032:analysis*
chemical_list: D007527:Isoenzymes; D005723:gamma-Glutamyltransferase; D009708:Nucleotidases; D000469:Alkaline Phosphatase