HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Leinbach, G. E. Articles by Nelp, W. B. Search for Related Content PubMed PubMed Citation Articles by Leinbach, G. E. Articles by Nelp, W. B.

Radiotriolein Revisited: A Study of the ¹³¹I-Triolein Absorption Test Using Radiochemically Pure Triolein in Man

University of Washington School of Medicine, Seattle, Washington

Correspondence: For reprints contact: Wil B. Nelp, Div. of Nuclear Medicine, University of Washington School of Medicine, Seattle, Wash. 98105.

ABSTRACT

Results of the ¹³¹I-triolein absorption test correlate poorly with chemical fecal fat balances. It has been shown that numerous radiochemical impurities are present in radioiodinated triolein. To test the hypothesis that these impurities are responsible for this poor correlation, commercial radioiodinated triolein was purified to greater than 98 % radiochemical purity and fed to 44 subjects during 3-day chemical fat-balance studies. These subjects included 15 normal volunteers (Group I), ten subjects with intestinal disease but without chemical fat malabsorption (Group II), and 19 subjects with steatorrhea of various etiologies (Group III). Whole-blood, plasma, plasma lipid, urine, and fecal radioactivities were measured after ingestion of the labeled test meal. Results obtained with radiochemically purified ¹³¹I-triolein (PRITO) were better than previously reported results using unpurified radioiodinated triolein (RITO). Blood radioactivity levels within the normal range were seen in 11% of patients with steatorrhea, but normal fecal radioactivity levels were found in only 4% of this same group. The 15 normal volunteers had both normal peak levels of whole blood radioactivity and normal fecal radio-activity. Sixteen of the 19 subjects with malabsorption had both excessive fecal radioactivity and low levels of whole blood radioactivity. Thus when both parameters were normal, chemical fat absorption was normal; when both parameters were abnormal, steatorrhea was present. The remaining three subjects in Group III and four subjects in Group II had one or the other of these two parameters abnormal. Whole-blood and plasma radioactivity determinations gave identical results; plasma lipid and urinary radioactivity levels were of no value because of the wide overlap between groups. There was no correlation between the amount of ¹³¹I and the amount of chemical fat excreted in the stool. It is concluded that the radiochemical purification of radioiodinated triolein improves the accuracy of this absorption test of fat malabsorption. However, the inability to quantitate fat malabsorption and the need for a 3-day collection of stool limit the usefulness of this absorption test in screening patients for suspected steatorrhea.