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Test Code POU_F Phosphorus, Feces


Ordering Guidance


This test is only clinically valid if performed on watery specimens. In the event a formed fecal specimen is submitted, the test will not be performed.



Specimen Required


Patient Preparation: No barium, laxatives, or enemas may be used for 96 hours prior to start of, or during, collection.

Supplies: Stool containers - 24, 48, 72 Hour Kit (T291)

Container/Tube: Stool container

Specimen Volume: 10 g

Collection Instructions: Collect a very liquid stool specimen.


Useful For

Workup of cases of chronic diarrhea

 

Identifying the use of phosphate-containing laxatives contributing to osmotic diarrhea

Method Name

Photometric, Ammonium Molybdate

Reporting Name

Phosphorus, F

Specimen Type

Fecal

Specimen Minimum Volume

5 g

Specimen Stability Information

Specimen Type Temperature Time Special Container
Fecal Frozen (preferred) 14 days
  Refrigerated  7 days
  Ambient  48 hours

Reference Values

An interpretive report will be provided

Interpretation

Phosphorus elevation above 102 mg/dL is suggestive of phosphate-induced diarrhea.(4)

Clinical Reference

1. Steffer KJ, Santa Ana CA, Cole JA, Fordtran JS: The practical value of comprehensive stool analysis in detecting the cause of idiopathic chronic diarrhea. Gastroenterol Clin North Am. 2012;41:539-560

2. Ho J, Moyer TP, Phillips SF: Chronic diarrhea: the role of magnesium. Mayo Clin Proc. 1995;70:1091-1092

3. Fine KD, Santa Ana CA, Fordtran JS: Diagnosis of magnesium-induced diarrhea. N Engl J Med. 1991;324:1012-1017

4. Fine KD, Ogunji F, Florio R, Porter J, Ana CS: Investigation and diagnosis of diarrhea caused by sodium phosphate. Dig Dis Sci. 1998;43(12):2708-2714

5. Eherer AJ, Fordtran JS: Fecal osmotic gap and pH in experimental diarrhea of various causes. Gastroenterology. 1992;103:545-551

6. Casprary WF: Diarrhea associated with carbohydrate malabsorption. Clin Gastroenterol. 1986;15:631-655

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

84100

LOINC Code Information

Test ID Test Order Name Order LOINC Value
POU_F Phosphorus, F 88713-3

 

Result ID Test Result Name Result LOINC Value
POU_F Phosphorus, F 88713-3

Day(s) Performed

Monday, Thursday

Report Available

1 to 3 days