Effect of Storage Time and Temperature on Fecal Leukocytes and Occult Blood in the Evaluation of Travelers' Diarrhea.

Both the presence of fecal leukocytes and occult blood in stool specimens of travelers with diarrhea have been used as indicators of colonic inflammation due to bacterial infection. This study was conducted to determine if storage temperature of stool specimens can affect the detection of leukocytes and occult blood. Sixteen specimens positive for occult blood and 23 specimens positive for leukocytes were divided into two aliquots. Each aliquot was held at 4 degreesC or 25 degreesC and reexamined daily for fecal leukocytes or occult blood. Four percent of the positive leukocytes specimens and 56% of the occult blood positive specimens were still positive on the fifth day when they were held at 4 degreesC. When the samples were held at 25 degreesC, leukocytes could not be detected after 3 days, but 19% were positive for occult blood on the fifth day. The results indicate that storage temperature of stool specimens was associated with a difference in detection rate.