Ammonia

Pathology category

Biochemistry

Code

AMM

Referral code

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Test information

To help diagnose severe liver disease and certain genetic urea cycle disorders. Blood ammonia increases in infants relative to adults because of the continuing development of hepatic circulation after birth. Sick pre-term infants may present with increased ammonia (up to 200 nmol/L) in the absence of any clinical findings. Infection should always be considered as a possible cause. Other more specific causes are as follows: inherited metabolic disorder, transient hyperammonaemia, IV feeding, infection, liver disease, Valproate, Reye’s syndrome.

Guidelines

MetBio.Net-Hyperammonaemia-Guidelines-2024-Final.pdf

BIMDG Undiagnosed Hyperammonaemia Guidelines, 2008

Pre-analytical

On ice, to be received in lab within 15min collection. Samples should ideally be walked to the lab rather than sent through the pneumatic tubes to reduce the risk of haemolysis.

Reference range

<1M sick or Prem: <150 µmol/L

<4weeks old: <100 µmol/L

4weeks  – 16 yrs old: <50 µmol/L

Adult: 0-40 µmol/L

Tube type

Tube type info

EDTA

Special requirements

Plasma (separated within 15-30 min collection)

Minimum volume

0.5 mL

Assay frequency

Run daily at both the Alex and WRH.

TAT Inpatient (urgent)

1.5 hrs

TAT Inpatient

4 hrs

TAT GP/Outpatient

24 hrs

Referral lab

Local, Clinical Biochemistry