Fecal Leukocytes

The presence of fecal leukocytes indicates bowel mucosal inflammation, which occurs in invasive bacterial enteritis and ulcerative colitis. The sensitivity of the fecal leukocyte test is approximately 70% for diarrheal disease caused by Shigella, but lower for other bacterial pathogens. Even in a children’s hospital setting, the sensitivity of fecal leukocyte test for bacterial pathogens is only 65%.

The fecal leukocyte test should not be ordered on patients developing diarrhea after more than 3 days hospitalization, because the likelihood of bacterial enteritis is very low.

Fecal leukocyte counts are not reliable enough to be used when infectious diarrhea must be ruled out with a high degree of certainty, such as the evaluation of an immunocompromised patient. Culturing the stool is more cost efficient in these circumstances.

Reference value is no WBC’s seen.

Specimen requirement is stool submitted as a smear on a glass slide, on a CulturetteÒ swab, or in a sterile, screw-capped container.


  1. Siletti RP etal. Role of Stool screening tests in diagnosis of inflammatory bacterial enteritis and in selection of specimens likely to yield invasive pathogens. J Clin Microbiol 1996;34:1161-65.
  2. Savola, KL etal. Fecal leukocyte stain has diagnostic value for outpatients but not inpatients. J Clin Microbiol 2001;39:266-69.
  3. Choi SW, etal. To culture or not to culture: fecal lactoferrin screening for inflammatory bacterial diarrhea. J Clin Microbiol 1996;34:928-32.
  4. Guerrant RL, etal. Measurement of fecal lactoferrin as a marker of fecal leukocytes.
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