Ammonia

Label Mnemonic:	PNH3
Epic code:	LAB47
Downtime form:	A-1a Doctor/Provider Orders - Pathology Core and Specialty Care Nursery

Chemistry
6240 RCP
356-3527

Specimen(s):

Plasma

Collection Medium:

Lavender top tube 3 mL (EDTA)

Alternate Collection Media:

Heelstick specimens are highly discouraged due to risk of artifactually elevated ammonia levels. or Call laboratory for additional acceptable specimen collection containers.

Minimum:

Full 3 mL lavender top (EDTA) tube or ONE lavender top (EDTA) microtube for pediatric patients.

Rejection Criteria:

Syringe is not acceptable.

Delivery Instructions:

Mix well and place on wet ice. Keep on ice and deliver to laboratory immediately.

Testing Schedule:

24 hrs/day, 7 days a week, including holidays.

Turn Around Time:

1 hour (upon receipt in laboratory)

Reference Range:

Birth to 48 hours old: 64-107 μmol/L
2 days old to 30 days old: 56-92 μmol/L
1 month to 18 years: 21-50 μmol/L

Male: 11-51 μmol/L
Female: 16-60 μmol/L
Clinically significant: >150 μmol/L (<18 years old only)

Comments:

This test is also performed in the Iowa River Landing (IRL) clinical laboratory (for specimens drawn at that site).

Test Limitations:

Criterion: recovery within plus or minus 10% of initial values

Icterus: No interference up to an I index of 30 (approximate 
conjugated 
and unconjugated bilirubin concentration: 30 mg/dL).

Hemolysis: No interference up to an H index of 200 (approximate 
hemoglobin concentration: 200 mg/dL).

Lipemia (Intralipid): No interference up to an L index of 150.  There 
is poor correlation between turbidity and triglycerides 
concentration. 
Absorbance flagging may also be observed as a result of an absorbance 
increase.

Methodology:

Enzymatic

CPT Code:

82140

See Additional Information:
Specimens Requiring Immediate Delivery