Clinical value of dual-isotope fat absorption test system (FATS) using glycerol [125I]trioleate and glycerol [75Se]triether.
In order to delineate the clinical value of a dual-isotope fat absorption test system (FATS) using glycerol [75Se]triether as lipid-phase marker and glycerol [125I]trioleate as the test lipid, fecal isotope ratios from single stools (and a 72-hr stool homogenate) were compared to quantitative fecal fat excretion. The study included 11 patients without and 24 patients with steatorrhea. With a figure of 0.8% as the upper limit of normal, the test was a reliable indicator of steatorrhea with 87.5% sensitivity and 81.8% specificity; efficiency was 85.7%. Related to a prevalence of steatorrhea of 45.9% as the mean value of 1269 consecutive 72-hr specimens investigated for steatorrhea during 1978-1982, the positive (negative) predictive value of the FATS is 80.3% (87.2%). With 2% as the upper limit of normal, no false positive results ensued. It is concluded that a two-step interpretation of the FATS (0.8% limit and 2% limit) may be regarded a valid qualitative index for steatorrhea. The FATS isotope ratio using single stools correlated well with FATS ratios in the 72-hr stool homogenates (r = 0.97). FATS therefore allows a convenient estimate of steatorrhea from measuring single stools. As a quantitative measure of fecal fat excretion, the FATS is unreliable.
D000328:Adult; D000368:Aged; D002446:Celiac Disease / Q000175:diagnosis*; D005223:Fats / Q000378:metabolism*; D005243:Feces / Q000032:analysis*; D005260:Female; D005990:Glycerol / Q000031:analogs & derivatives; D006801:Humans; D007408:Intestinal Absorption; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D012643:Selenium; D013997:Time Factors; D014304:Triolein
D005223:Fats; D007457:Iodine Radioisotopes; D014304:Triolein; C007868:glycerol triether; D012643:Selenium; D005990:Glycerol