Type of test Stool
Normal findings
None detected
Test explanation and related physiology
Lactoferrin is a glycoprotein expressed by activated neutrophils. The detection of lactoferrin in a fecal sample therefore serves as a surrogate marker for inflammatory white blood cells (WBCs) in the intestinal tract. WBCs in the stool are not stable and may be easily destroyed by temperature changes, delays in testing, and toxins within the stool. As a result, WBCs may not be detected by common microscopic methods. Lactoferrin assay has allowed the identification of inflammatory cells in the stool without the use of microscopy.
Detection of fecal lactoferrin allows for the differentiation of inflammatory and noninflammatory intestinal disorders in patients with diarrhea. Usually the test is used as a diagnostic aid to help identify patients with active inflammatory bowel disease (e.g., Crohn disease or ulcerative colitis) and to rule out those with active irritable bowel syndrome, which is non inflammatory. Lactoferrin is also present in patients with bacterial enteritis (e.g., Shigella spp., Salmonella spp., Campylobacter jejuni, and Clostridium difficile). Diarrhea caused by viruses and most parasites is not associated with elevated lactoferrin levels.
Interfering factors
• The stool specimen should be examined immediately. In some instances, a specific stool preservative–enteric transport media can be used.
• Breastfeeding can affect test results in breastfed infants.
Procedure and patient care
Before
* Explain the procedure to the patient.
* Instruct the patient not to mix urine or toilet paper with the specimen.
During
• Stool is collected in a clean bedpan.
• Place at least 5 g of stool in a clean specimen container.
After
• Observe appropriate contamination precautions.
• Transfer the specimen to the laboratory immediately.
* Inform the patient that results are usually available in less than a half hour.
Abnormal findings
- Bacterial enteritis
- Crohn disease
- Ulcerative colitis
