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Test Code COHB Carboxyhaemoglobin, Blood

Important Note

Therapeutic levels (1 mg/mL and 2 mg/mL) of Hydroxocobalamin may interfere with COHB assay. Do not expose specimen to air. Specimen should be completely without air bubbles. Mix sample well to prevent clotting. Chill specimen and send to laboratory immediately.

Additional Codes

Epic Ordering Code LAB56
NBS code LBC04059
Service code 31005

Specimen Requirements

Submit only one of the following:

Preferred: Acceptable:
Heparinized Syringe Capillary

Processing Requirements

Place specimen in ice and send to laboratory immediately. 

Specimen type: Whole Blood

Volume: 1mL

Specimen Stability

Specimen Type Whole Blood
Ambient Reject
Refrigerate 5 mins (ice slurry)
Frozen Reject

Specimen Condition

Haemolysis Not applicable
Icterus Not applicable
Lipaemia Not applicable
Others: Sample not sent in ice, sample not sealed, bubbles present in sample, clotted sample   Reject 

Methodology

CO-oximetry

Days and Times Performed

24 hrs, TAT 1 day

Reference Interval

Potentially toxic: > 15.0%

Testing Laboratory

National University Hospital

Clinical Chemistry, 67724346

Useful For

Diagnosis of carboxyhemoglobinemia.

Update

Last updated 27/06/2026

LOINC Code Information

2030-5