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Test Code LEU Fecal Leukocytes, Feces

Reporting Name

Fecal Leukocytes

Useful For

Suggesting the presence of pathogens such as Salmonella, Shigella, and amebiasis

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Fecal


Specimen Required


Supplies: ECOFIX Stool Transport Medium only (T790)

Container/Tube:

Preferred: ECOFIX preservative

Acceptable: Zinc Polyvinyl alcohol (Zn-PVA) preservative

Specimen Volume: Representative portion of collection

Collection Instructions:

1. Collect a random fecal specimen.

2. Carefully follow instructions on container.

a. Place specimen into ECOFIX preservative vial OR Zinc-PVA preservative vial within 30 minutes of passage or collection. Refer to the fill line on the preservative vial. Do not fill above the line indicated on the container.

b. Mix the contents of the tube with the spoon, twist the cap tightly closed, and shake vigorously until the contents are well mixed.


Specimen Stability Information

Specimen Type Temperature Time Special Container
Fecal Ambient (preferred) 21 days PVA OR ECOFIX
  Refrigerated  21 days PVA OR ECOFIX

Reference Values

An interpretive report will be provided.

Day(s) Performed

Monday through Saturday

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

89055

LOINC Code Information

Test ID Test Order Name Order LOINC Value
LEU Fecal Leukocytes 13655-6

 

Result ID Test Result Name Result LOINC Value
LEU Fecal Leukocytes 13655-6

Clinical Information

Leukocytes are not normally seen in feces in the absence of infection or other inflammatory processes. Fecal leukocytosis is a response to infection with microorganisms that invade tissue or produce toxins, which causes tissue damage.

 

Fecal leukocytes are commonly found in patients with shigellosis and salmonellosis and sometimes in amebiasis. Mononuclear cells are found in typhoid fever.

 

Ulcerative colitis may also be associated with fecal leukocytosis.

Interpretation

When fecal leukocytes are found they are reported in a semi-quantitative manner: "few" indicates = 2/100x oil immersion microscopic field (OIF); "moderate" indicates 3-9/100x OIF; "many" indicates =10/100x OIF. Erythrocytes are reported in the same manner.

 

The greater the number of fecal leukocytes, the greater the likelihood that an invasive pathogen such as Salmonella or Shigella is present.

 

The presence of few or no leukocytes and many erythrocytes suggests possible amebiasis.

 

Fecal leukocytes are rarely seen in diarrhea caused by other parasites or viruses. 

Cautions

Fecal leukocyte examinations cannot be performed on formalin-preserved specimens. Therefore, ECOFIX-preserved or zinc polyvinyl alcohol-preserved feces must be sent to the laboratory.

Clinical Reference

1. LaRocque RC and Harris JB: Syndromes of Enteric Infection. In: Bennett JE, Dolin R, and Blaser MJ, eds.  Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases. 9th ed. Elsevier; 2020:chap 96

2. Harris JC, Dupont HL, Hornick RB. Fecal leukocytes in diarrheal illness. Ann Intern Med. 1972;76(5):697-703. doi:10.7326/0003-4819-76-5-697

3. Guerrant RL, Shields DS, Thorson SM, Schorling JB, Gröschel DH. Evaluation and diagnosis of acute infectious diarrhea. Am J Med. 1985;78(6B):91-98. doi:10.1016/0002-9343(85)90370-5

4. Pickering LK, DuPont HL, Olarte J, Conklin R, Ericsson C. Fecal leukocytes in enteric infections. Am J Clin Pathol. 1977;68(5):562-565. doi:10.1093/ajcp/68.5.562

Method Description

Feces preserved in ECOFIX preservative or polyvinyl alcohol are stained with trichrome.(Garcia LS: Diagnostic Medical Parasitology. 6th ed. ASM Press; 2016)

Report Available

4 to 6 days

Specimen Retention Time

7 days

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Method Name

Microscopic/Trichrome Stain

Forms

If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.

Secondary ID

8046

Specimen Minimum Volume

5 mL