Carboxyhemoglobin (COHb)

Specimen Type

Test ID LAB56
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 syringe, or Green top heparin tube. Acceptable tubes are Lithium Heparin-NO GEL or Sodium Heparin; See Important Comments
Micro: 0.5 mL whole blood in syringe w/ lyophilized heparin in BG kit.
Availability Routine: 24 Hours/Day
Turnaround Time 10 minutes
Reference Range Normal: See Table Below
Critical: >20%
  • Deliver Immediately.
  • Samples should be delivered to the laboratory for testing within 30 minutes of collection. Samples are acceptable up to 24 hrs (whole blood; do not freeze).
  • Syringes with needles attached will NOT be accepted.

Reference Ranges: Carboxyhemoglobin
Non-Smoker Avg. Smoker Heavy Smoker
0.0-1.5% 4-5% 6-8%

Reviewed by Christopher Parker on December 09, 2021

Note: Reference ranges provided on this web site are for guidance only, and may not reflect the most recent changes. Refer to laboratory reports for current reference data.

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