Health Lab

Test Name:

AMMONIA, PLASMA

Test Code:

2120289

Alias:

LAB47
NH3
NH4

CPT Code(s):

82140

Preferred Specimen:

3.0 mL plasma

Draw one EDTA (lavender) for this test only. Do not combine with other tests.

Container:

EDTA (lavender)

Tubes must be filled completely.

Collection Instructions:

Patient prep: Collect blood from stasis-free vein of a fasting patient. Smoking should be avoided prior to sampling.

Tubes must be filled completely and kept tightly stoppered at all times. Place specimen on ice immediately. If testing will not occur within 30 minutes, allow specimen to chill on ice for 10 minutes and then centrifuge for 3 minutes. Immediately transfer plasma into a properly labeled plastic transfer tube and freeze.

Transport Temperature:

Frozen

Stability:

Frozen: 24 hours

Rejection Criteria:

Capillary specimens

Hemolysis

Lipemia

Specimen received unfrozen

Frozen whole blood specimens

Limitations:

Smoking increases plasma ammonia levels.

The ammonia level will be affected if it is not handled properly.

Additional Information:

Capillary collections are not acceptable.

Schedule:

Set up: Daily; Results in 24 hours

Method:

Enzymatic

Clinical Significance:

Circulatory ammonia levels in normal individuals are relatively low despite the fact that ammonia is continuously produced from dietary and amino acid metabolism. Monitoring blood ammonia levels can be useful in the diagnosis of hepatic encephalopathy and hepatic coma in the terminal stages of liver cirrhosis, hepatic failure, acute and subacute necrosis, and Reye’s syndrome. Hyperammonemia in infants may be an indicator of inherited deficiencies of the urea cycle metabolic pathway.

Critical Values:

>200 umol/L (CDH only)

Use:

Updated 1/30/2023

Reference Range Table

Result	Units	Gender	Age	Range
Ammonia	mcmoles/L	Both	0 Year - 999 Year	11-60

The CPT codes included in this publication are in accordance with Current Procedural Terminology, a publication of the American Medical Association. CPT codes are provided here for the convenience of our clients; however, correct coding often varies from one carrier to another, and HealthLab may bill specific carriers using codes other than those shown. Clients who bill for services should verify the code(s) with the applicable payor to confirm that their use is appropriate in each case.