Shastri YM et al. (2008) Prospective multicenter study evaluating fecal calprotectin in adult acute bacterial diarrhea. Am J Med 121: 1099–1106

Acute, bacterial diarrhea can be severe and, in some cases, life-threatening. The standard method with which to diagnose acute, infectious diarrhea is bacteriological culture; however, this technique is time-consuming and expensive. Rapid, inexpensive screening methods are, therefore, needed. A study by Shastri et al. has demonstrated the accuracy of using fecal calprotectin to diagnose acute, bacterial diarrhea.

The study compared the diagnostic accuracy of three tests: fecal calprotectin, fecal lactoferrin and the guaiac-based fecal occult blood test (FOBT). Stool samples from 2,185 patients with acute diarrhea were analyzed by performing cultures for the identification of different enteral pathogens. Samples from patients with a positive microbial diagnosis (n = 195) and controls with a negative microbial diagnosis (n = 196) were then subjected to the three different tests. The sensitivity and specificity of the fecal calprotectin test were 82.6% and 87.2%, respectively, compared with 77.9% and 53.6% for the fecal lactoferrin test and 37.9% and 84.7% for the FOBT. Of note, results from the fecal calprotectin test could be generated within hours.

The superior correlation of the calprotectin test findings with bacteriological, infectious diarrhea suggests that calprotectin is a suitable screening marker for bacterial diarrhea. Stool samples that test positive for calprotectin should then be cultured to provide a definitive diagnosis. Use of this technique should reduce associated costs and, more importantly, the time taken to achieve diagnosis, which leads to improved prognosis for patients.