Ammonia (Blood)

Testing Laboratory

Auckland Te Toka Tumai | Auckland Hospital

Department

Chemical Pathology

Delphic Registration Code (Alpha Code)

Venous/ Arterial Blood: MAMM/0436
Capillary Blood CAMM/0434
Unknown: AMM/4067

Test Code (Numeric Code)

0436

Laboratory Handling

Phlebotomy

Please phone LabPlus to give advance warning a sample is being sent.
Mark the form as "URGENT".

Transport

Within Auckland City Hospital: Transport specimen on ice without delay.
If sending from outside Auckland City Hospital: Separate immediately and send on ice without delay.

Registration

NOTE: A separate EDTA sample NOT ON ICE is required if a FBC is also requested.

Laboratory

See Laboratory Notes section under 'Additional Information' at end for special instructions.

Sample Stability

30 mins at 15-25°C, 2 hours at 2-8°C, 3 days at -20°C

Synonyms

Ammonia Blood (venous/arterial)
NH3

Turnaround Time

3 hours

Specimen Type

• Plasma

Specimen Requirements

Tube/Container Type:

Preferred

• EDTA (Lavender Cap)

Preferred Sample Volume (ml)

4

Minimum Sample Volume (ml)

4

No of Samples Required

1

Paediatric Specimen Requirements

Tube/Container Type:

Preferred

• EDTA (Microtainer)

Preferred Sample Volume (ml)

0.5

Minimum Sample Volume (ml)

0.5

Additional Specimen Information

Specimen Collection:
- Please phone LabPlus to give advance warning a sample is being sent.

Transport of sample:
- Within Auckland City Hospital: Transport specimen on ice without delay .
- If sending from outside Auckland City Hospital: separate immediately and send on ice without delay.

Mark the form as "URGENT"
- The ammonia level rises in stored plasma due to ammonia generation from precursors.
- Samples from outside Auckland City Hospital: If separated samples transported on ice are analysed within 2 hours the increase in ammonia will be insignificant.
- Auckland Hospital samples: if whole blood samples on ice are separated within 1 hour and analysed within 2 hours of collection, the increase will be insignificant.
- A minimum 2 mL specimen is preferred. The test can be performed on a micro-sample, but sweat contamination will increase the ammonia concentration significantly, which makes result interpretation difficult. The skin must be thoroughly cleaned prior to collection of the specimen.

NOTE: A separate EDTA sample NOT ON ICE is required if a FBC is also requested.

Aliquot Instructions

Sample Type

• Plasma

Transport to Lab

Chilled (2 - 8 degrees Celsius)

Additional Referral/Aliquot Information

Within Auckland City Hospital: Transport specimen on ice without delay.
If sending from outside Auckland City Hospital: separate immediately and send on ice without delay.

Test Method

Test performed by: LabPlus Automation
Principle: Enzymatic
Reagents: Roche Assay
Analyser: Roche Cobas

Limitations / Interference

Note: the drugs sulfasalazine and sulfapyridine cause interference in the assay; patients on these drugs may have invalid ammonia results.

Uncertainty of Measurement

8% for results around 50 umol/L.
8% for results around 100 umol/L.

Laboratory Notes:
- All Ammonia samples: Separate as soon as possible at 4°C and hand deliver to c8100 operator - tell them it is an Ammonia. See below for additional information.
- GLCC- please separate and send on ice.

Specimen Services:
If sample received is NOT on ice:
- Write 'not received on ice' on request form.
- Separate sample at 4°C as soon as possible.
- Give a photocopy of the form along with the separated sample to the c8100 operator.
- Tell the c8100 operator it is an ammonia.

If both Ammonia and FBC requested and only 1 EDTA sample is received but NOT ON ICE:
- Register for both Ammonia and FBC.
- Write 'not received on ice' on request form.
- Send sample to Haematology for FBC.
- Give a photocopy of the form to the c8100 operator.
- Tell the c8100 operator the EDTA tube is sent to Haematology for FBC.

If both Ammonia and FBC requested and only 1 EDTA sample is received ON ICE:
- Register for Ammonia.
- Register a Query Correct Specimen for the FBC (code: QHAE) .
- Specimen sent on ice is NOT suitable for FBC.

If sample type not specified:
- Register using the code AMM/4067 - This is Ammonia (unknown).

Automation Staff:
- All Ammonia samples should be processed.
- Refer to the Ammonia method SOP for guidelines to processing and reporting samples not received on ice or >2 hours old.

Contact Information