Ammonia

Alphabetical Test listing

Ammonia-27

Test name:

Ammonia

Test number:

Excellian order number:

82140

Abbreviation:

AMM

Alternate names:

NH3

Useful for:

Ammonia, derived from the catabolism of amino acids and from the action of intestinal bacteria on dietary protein, is converted to urea in the liver hepatocytes and so rendered non-toxic. Studies have shown that excess ammonia can have a toxic effect on the central nervous system and clinical manifestations are typically neurological disturbances. Elevated levels of ammonia may be either due to "Inborn Errors of Metabolism", or secondary to other conditions.

Inborn errors of metabolism are the major cause of elevated ammonia in infants and usually the result of urea cycle enzyme deficiencies. Inherited disorders affecting the metabolism of the dibasic amino acids (lysine and ornithine) and those involving the metabolism of organic acids may also produce elevated levels of circulating ammonia. Elevated ammonia may also be observed in severe liver failure as may occur in Reye’s syndrome, viral hepatitis or cirrhosis.

Limitations:

This test cannot be added on to a previous specimen

Specimen type:

EDTA plasma

Collection container:

Lavender (EDTA), 4mL

Volume:

1.0 mL

Minimum volume:

0.2 mL

Collection instructions:

Following collection, mix sample by inverting 8 - 10 times to prevent clotting
Immediately place sample on ice

Processing instructions:

Spin and transfer plasma to a False bottom plasma/serum transport vial/tube (AHL), labelled as EDTA plasma, within 30 minutes of collection. If separation is delayed, the results may be falsely elevated.
If the specimen will not be tested within 1 hour of collection, the plasma must be frozen at <-20°C.

Transport container:

False bottom plasma/serum transport vial/tube (AHL)

Transport and stability:

Frozen (preferred) - 3 days

Refrigerated - 2 hours

Ambient - 30 minutes

Reason for rejection:

Hemolysis
- Erythrocytes contain approximately 3 times more ammonia than does plasma
Specimens should not be repeatedly frozen and thawed
Specimens should be free of particulate matter and red blood cells
Improper labels (unlabeled or mislabeled)
Improper anticoagulant or ratio
Delay in transport
Improper storage temperature affecting results
Inappropriate timing of collection
Improper container
Leaking container resulting in compromised specimen
Quantity not sufficient (QNS)

Performing lab:

AHL - Chemistry: C

Days set up:

Daily

TAT:

1 day

Method:

Enzymatic

Reference ranges:

Male	11 - 51 µmol/L
Female	16 - 60 µmol/L

Results that require action (critical):

>110 µmol/L

CPT codes:

82140

Date created:

11/30/2001

Revised date:

10/23/2023

Review date:

01/04/2024