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        There are several different diagnostic stool tests for
malabsorption, however, there are not specific for CD. Some of the old
textbooks still suggest stool fat determination as part of the diagnosis
of CD. A simple fat sample is inappropriate for this purpose. For a real
guantitative analysis of stool fat content,  the patient should be on a
well-defined diet, with known fat content two days before the stool
collection and for three another days when all the stool is collected. The
laboratory measures the total fat content during the three-day period and
a the ratio of stool fat / ingested fat is calculated. Normally, more than
95 % of ingested fat is absorbed in the small intestine. In my experience,
the sensitivity of this complicated quantitative stool-fat-test was below
60% in my patients with CD. So I decided not to use it.
        Other tests are determining unabsorbed sugars in the stool. They
are also not sensitive and specific.
        The conclusion is that the stool tests have limited value in the
diagnosis of celic disease. The blood serology test has a higher
sensitivity ans specificity, and the intestinal biopsy still remains the
gold-standard.
 
Karoly Horvath, M.D.
Baltimore