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Test Code NITF Nitrogen, Total, Feces

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Fecal


Shipping Instructions


Send entire stool collection (must contain at least 5 g of feces) frozen on dry ice in Mayo Clinic Laboratories-approved container.



Necessary Information


Length of collection period is required.



Specimen Required


Patient Preparation: Laxatives and enemas should not be used during collection as barium and boric acid interfere with test procedure.

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

Container/Tube: Stool container; complies with shipping requirements, do not use other containers.

Specimen Volume: Entire collection (24, 48, 72, or 96 hours)

Collection Instructions:

1. All containers must be sent together.

2. Entire collection must contain at least 5 g of feces.

3. The number of containers sent should be indicated on the labels (ie, 1 of 4)

Specimen Stability Information: Frozen 3 years

Additional Information: Patient can store sample at refrigerate temperature during collection period.


Specimen Minimum Volume

See Specimen Required

Specimen Stability Information

Specimen Type Temperature Time
Fecal Frozen (preferred)
  Ambient  7 days
  Refrigerated  7 days

Reference Values

<16 years: Not established

≥16 years: 1-2 g/24 hours

CPT Code Information

84999

Clinical Information

Nitrogen is a key component of proteins. Nitrogen balance is the difference between the amount of nitrogen ingested and the amount excreted in the urine and feces. A majority of nitrogen is excreted as urea in the urine; however, fecal nitrogen can account for 30% to 50% of total nitrogen excretion.

 

A patient who is in negative nitrogen balance is catabolizing muscle protein to meet the metabolic requirements of protein catabolism; therefore, urine and fecal nitrogen concentrations may be increased due to stress, physical trauma, surgery, infections, burns, and 11-oxysteroid or thyroxine use. Testosterone and growth hormone have anabolic effects on protein synthesis and may decrease urine and fecal nitrogen levels.

 

In the course of chronic progressive pancreatitis, as the pancreas is destroyed, serum amylase and lipase may revert to normal. However, excessive fecal nitrogen levels persist and are used as an indicator of pancreatic atrophy.

Reject Due To

Urine and stool mixed Reject

Method Name

Dumas Combustion

Day(s) Performed

Friday

Report Available

1 to 8 days