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
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.
Minimum:
Full 3 mL lavender top (EDTA) tube or ONE lavender top (EDTA)
microtube for pediatric patients.
Rejection Criteria:
Syringe is not acceptable. Specimens received not on ice will be cancelled. Specimens received on ice, but after 30 minutes from collection will also be cancelled.
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
Clinically significant: >150 μmol/L (<18 years old only)
Male: 16-60 μmol/L
Female: 11-51 μmol/L
2 days old to 30 days old: 56-92 μmol/L
1 month to 18 years: 21-50 μmol/L
Clinically significant: >150 μmol/L (<18 years old only)
Male: 16-60 μmol/L
Female: 11-51 μmol/L
Comments:
This test is also performed in the Iowa
River Landing (IRL) clinical laboratory (for specimens drawn at that
site).
Test
Limitations:
Therapeutic concentrations of the following drugs may lead to erroneous ammonia results: Cefoxitin (artificially high ammonia results), Intralipid (artificially high ammonia results), Sulfasalazine, and Temozolomide.
Icterus: No interference up to an I index of 60 (approximate conjugated and unconjugated bilirubin concentration: 60 mg/dL).
Hemolysis: No interference up to an H index of 100 (approximate hemoglobin concentration: 100 mg/dL).
Lipemia (Intralipid): No interference up to an L index of 700. There is poor correlation between turbidity and triglycerides concentration.
Therapeutic concentrations of the following drugs may lead to erroneous ammonia results: Cefoxitin (artificially high ammonia results), Intralipid (artificially high ammonia results), Sulfasalazine, and Temozolomide.
Icterus: No interference up to an I index of 60 (approximate conjugated and unconjugated bilirubin concentration: 60 mg/dL).
Hemolysis: No interference up to an H index of 100 (approximate hemoglobin concentration: 100 mg/dL).
Lipemia (Intralipid): No interference up to an L index of 700. There is poor correlation between turbidity and triglycerides concentration.
Therapeutic concentrations of the following drugs may lead to erroneous ammonia results: Cefoxitin (artificially high ammonia results), Intralipid (artificially high ammonia results), Sulfasalazine, and Temozolomide.
Methodology:
Enzymatic
Updated to Roche Cobas Ammonia Generation II assay on 06/16/2020.
Updated to Roche Cobas Ammonia Generation II assay on 06/16/2020.
CPT Code:
82140
See Additional Information:
Specimens Requiring Immediate Delivery
Specimens Requiring Immediate Delivery