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Fecal Lactoferrin Assay

WBC, leukocytes, Gram Stain, methylene blue, inflammatory diarrhea, non-inflammatory diarrhea, Leuko EZ Vue

Test Codes

EPIC: LAB5513

Department

Microbiology

Instructions

1. The Fecal Lactoferrin test provides superior test results as compared to the Fecal Leukocytes (WBC) test. Therefore, all unpreserved stool specimens received in the laboratory from patients greater than or equal to 18 months of age will automatically be analyzed with the Fecal Lactoferrin test.
2. This test may be falsely positive if stool samples are tested on breast fed infants. In this situation, the Fecal Leukocytes (WBC) test should be ordered.
3. This test may be falsely negative if stool samples are tested on immunocompromised patients with decreased levels of neutrophils.

Specimen Collection Criteria

Collect: Random stool specimen in a sterile collection container with no preservatives.

Physician Office/Draw Specimen Preparation

Maintain specimen at room temperature (20-26°C or 68-78.8°F) or refrigerated (2-8°C or 36-46°F) prior to transport.

Preparation for Courier Transport

Transport: Stool specimen in a sterile collection container, at room temperature (20-26°C or 68-78.8°F) or refrigerated (2-8°C or 36-46°F).

Rejection Criteria

• Specimens that are in transport media.
• Specimens that have been preserved in 10% formalin, merthiolate formalin, sodium acetate formalin (SAF), polyvinyl alcohol (PVA), or other fixatives.
• Specimens collected from endoscopic procedures.
• Specimens submitted on a swab.
• Stool specimens received in non-approved containers (e.g., diapers, pill bottles, containers with wax lining, containers intended or used for food, other household containers, etc.).

Storage

Specimen Stability for Testing:

Room Temperature (20-25°C or 68-77°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days

Laboratory

Royal Oak Microbiology Laboratory

Performed

Sunday – Saturday, 24 hours a day.
Results available within 24 hours.

Reference Range

Negative.

Test Methodology

Immunochromatographic Assay.

Interpretation

Positive – Fecal lactoferrin, a surrogate marker for fecal leukocytes, was detected in this stool specimen indicating the presence of intestinal inflammation, that may be due to various clinical conditions (i.e., inflammatory diarrheal entities, inflammatory bowel disease, C. difficile colitis, etc.).

Negative – Fecal lactoferrin, a surrogate marker for fecal leukocytes, was not detected in this stool specimen. This does not exclude the presence of a number of non-inflammatory diarrheal entities (i.e., enteric viruses, enteric parasites, antibiotic associated, etc.).

Invalid – Interfering substances were present in this stool specimen. Please submit an additional specimen for analysis.

Clinical Utility

In brief, this test facilitates the qualitative detection of intestinal inflammation and the distinction between inflammatory and non-inflammatory causes of diarrhea. Inflammatory processes may be due to various clinical conditions, including inflammatory bowel disease or infections due to Shigella, Salmonella, Campylobacter, and toxigenic C. difficile. Non-inflammatory diarrhea may be related to viral and parasitic infections as well as antibiotic utilization.

Notes:
This test may be falsely positive if stool samples are tested on breast fed infants. In this situation, the Fecal Leukocytes (WBC) test should be ordered.

This test may be falsely negative if stool samples are tested on immunocompromised patients with decreased levels of neutrophils.

Clinical Disease

Diarrheal illnesses represent a major cause of morbidity worldwide, and in general are classified as inflammatory or non-inflammatory. Non-inflammatory diarrhea is commonly associated with viruses (i.e., rotavirus, norovirus, etc.), parasites (i.e., Cryptosporidium, Entamoeba, etc.), and antibiotics. Inflammatory diarrhea is usually caused by certain bacterial pathogens, including Shigella, Salmonella, Campylobacter, and toxigenic C. difficile. In inflammatory diarrhea, fecal leukocytes (WBCs) are found in the feces in large numbers. The determination of fecal leukocytes by microscopy is a procedure used by many laboratories; however, it has several disadvantages, including lack of standardization in staining methods and interpretative criteria, and is prone to false negative results due to leukocyte lysis.

Lactoferrin is a glycoprotein component of neutrophilic granules that is present within and released from leukocytes. Because of the relative stability of lactoferrin as compared to intact leukocytes, the detection of lactoferrin in feces is a very accurate surrogate marker of intestinal inflammation.

Reference

1. Harris, J.C., H.L. DuPont, and B.R. Hornick. 1971. Fecal leukocytes in diarrheal illness. Ann Intern Med. 76:697-703.
2. Guerrant, R.L., J.M. Hughes, and N.L. Lima, et al. 1990. Diarrhea in developed and developing countries; magnitude, special settings, and etiologies. Rev Infec Dis. 12:S41-50.
3. Guerrant, R.L., V. Arujo, and E. Soares, et al. 1992. Measurement of fecal lactoferrin as a marker of fecal leukocytes. J Clin Micro. 30;1238-1242.
4. Kane, S.V., W.J. Sandborn, and P.A. Rufo, et al. 2003. Fecal Lactoferrin Is a sensitive and specific marker in identifying intestinal inflammation. Amer J GastroEnt. 98(6):1309-14.
5. Dai, J., W-Z Liu, and Y-P Zhao, et al. 2007. Relationship between fecal lactoferrin and inflammatory bowel disease. Scan J GastroEnt. 42:1440-1444.

CPT Codes

83630

Contacts

Last Updated

4/4/2024