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Test Code COHB Carbon Monoxide, Blood

Additional Codes

Epic Code


Performing Laboratory

Bronson Laboratory Services-Chemistry

Reference Values


Nonsmoker: 0.0-2.5%

0.0-2.0 %

Smoker: up to 10%


Critical value (automatic call-back): ≥15.0% (If elevated >15.0%,

test is reported on any blood gas specimen

that is tested whether carboxyhemoglobin [COHb] is ordered or not.)

Critical value : >10%


Specimen Transport Temperature

Ambient or Refrigerate 7 days

Specimen Requirements

Specimen Type: Venous or arterial whole blood

Container/Tube: Green top (heparin)-Lavender-top (EDTA) tube or heparinized syringe is also acceptable.
Specimen Volume: 4 mL

Specimen Minimum Volume: 0.5 mL

Collection Instructions: Invert several times to mix blood. Do not centrifuge.


Spectrophotometry (SP)

Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding