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Test Code Ammon Ven Ammonia, Blood Venous

Important Note

NO MICROTAINERS. Read "Notes" under Sample Requirements before collection.

Place specimen in outside pocket of a pre-filled biohazard bag of ice, then put into biohazard bag for transport.

Clinical System Name

Ammonia, Blood Venous


Ammonia is a waste product of protein catabolism that is potentially toxic to the central nervous system.  Increased plasma ammonia may be indicitive of hepatic encephalopathy, hepatic coma in terminal stages of liver cirrhosis, hepatic failure, acute and subacute liver necrosis, and Reye's syndrome.  Hyperammonemia may also be found with increasing dietary protein intake.

Sample Requirements

Specimen:  Whole Blood

Container(s):  Dark Green/Sodium Heparin

Required Vol: At least 2.0 mL in an unopened 4.0mL Dark Green/Sodium Heparin

Minimum Vol: 0.5mL  (Syringe only)

Note:  Place specimen in separate bag and then in bag with ice.  For 4.0mL Dark Green/Sodium Heparin tubes, less than 1/2 full will be rejected. Do not remove vacutainer top to fill tube. Remove air bubbles from Heparinized Syringe immediately after collection.  A venous sample is preferable unless an arterial line is in place.

Processing Instructions

Reject due to: Insufficient quantity, age of specimen, specimen not transported correctly.

Spin: Yes

Aliquot: Yes. Transfer blood gas syringe contents to a bullet tube; centrifuge for 3 minutes.

Storage location:  Core 5 Refrigerator

Notes:  Method is affected by exposure to red blood cells and hemolysis.  Not affected by icterus or lipemia.


Off-site collection:   Note on requisition if sample is venous or arterial.  Place specimen in separate bag and then in bag with ice.  Centrifuge, remove plasma from cells (within 15 minutes), and freeze plasma ASAP.  Keep specimen frozen during transport. Plasma must be removed from red blood cells within 15 minutes for an accurate ammonia result.



Specimen Type Temperature Time
Whole Blood


≤ 15 m
Plasma RT


Plasma 2-4oC

≤ 3 Hours

Plasma -20o C or -70o C

≤ 24 Hours


Plasma must be removed from red blood cells within 15 minutes for an accurate ammonia level.


STAT Performed TAT
Y 24/7 1 H


Performing Laboratory

Seattle Children's Laboratory    


Department:  Core Lab Chemistry

Phone Number: 206-987-2617



Reference Range


Age uMol/L
0 - 3 days 9 - 107
3 days - 2 week 9 - 92
2 weeks - 2 months 9 - 50
2 months - adult 9 - 35


Ranges are established in venous plasma. Arterial plasma values will be lower.


Method:  Colorimetric method by Vitros 4600

Minimum Volume: 0.05 mL serum or plasma. 

Analytical Volume:  0.02 mL + 0.03 dead space.

CPT Codes