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Carboxyhemoglobin (COHb)

Specimen Type = 3 cc Syringe and green top

Specimen Type

Test ID LAB56
EPIC Order CARBOXYHEMOGLOBIN
CPT Code(s) 82375
Group/Individual Test Individual
Laboratory Core Laboratory-Blood Gas
Tube Station 31
Specimen Routine: 1 mL whole blood in 3cc syringe w/ lyophilized heparin in BG Kit, SafePICO Collection Kit, or Green Heparin – NO GEL. See Comments.
Micro: 0.5 mL whole blood in 1cc syringe w/ lyophilized heparin in BG Kit or full heparinized capillary tube. See Comments.
Stability  

Room Temperature/Refrigerated: up to 24 hours

Frozen: NO
Availability Routine: 24 Hours/Day
STAT: Yes
Turnaround Time 10 minutes
Reference Range Normal: See Table Below
Critical: >20%
Comments

    • Green Sodium Heparin tubes are NOT acceptable and will be rejected.

    • Deliver Immediately to Blood Gas lab.   

    • Syringes with needles attached will NOT be accepted.

    • Blood Gas syringes may be obtained from Central Distribution.

    • Heparinized capillary samples can be analyzed if at least 200 µL of clot-free blood is present.

    Reference Ranges: Carboxyhemoglobin
    Non-Smoker Avg. Smoker Heavy Smoker
    <1.2% 4-5% 6-8%

    Reviewed by J. Carr on January 15, 2026

    UNC Hospitals
    McLendon Clinical Laboratories
    101 Manning Drive
    Chapel Hill, NC 27514