This test is temporarily unavailable due to instrument issues. As an alternate, order FCMEB. For additional details, see test update here.
Verifying carbon monoxide toxicity in cases of suspected exposure
Carboxyhemoglobin Co-oximetry
Carboxyhemoglobin
CO (Carbon Monoxide)
Carbon Monoxide (Carboxyhemoglobin)
Whole Blood EDTA
This test is not available for autopsy or cadaver specimens.
Container/Tube: Lavender top (EDTA)
Specimen Volume: 1 mL
Collection Instructions:
1. Avoid exposure of specimen to atmosphere.
2. Send specimen in original collection tube. Do not aliquot.
If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.
0.1 mL
Gross hemolysis | OK |
Gross lipemia | OK |
Gross icterus | OK |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Whole Blood EDTA | Ambient (preferred) | 14 days | |
Frozen | 14 days | ||
Refrigerated | 14 days |
Verifying carbon monoxide toxicity in cases of suspected exposure
Carbon monoxide (CO) is a colorless, odorless, tasteless gas that is a product of incomplete combustion of carbonaceous material. CO poisoning causes hypoxia because CO binds to hemoglobin with an affinity 250 times greater than that of oxygen, thus preventing delivery of oxygen to the tissues. Concentrations greater than 20% are associated with symptoms of toxicity (eg, headache, fatigue, dizziness, confusion, nausea, vomiting, increased pulse and respiratory rate). CO levels greater than 50% are potentially fatal. Common exogenous sources of carbon monoxide include cigarette smoke, gasoline engines, and improperly ventilated home heating units. Small amounts of carbon monoxide are produced endogenously in the metabolic conversion of heme to biliverdin. This endogenous production of carbon monoxide is accelerated in hemolytic anemias.
Normal Concentration
Non-Smokers: 0-2%
Smokers: < or =9%
Toxic concentration: > or =20%
The toxic effects of carbon monoxide can be seen in levels above 20% carboxyhemoglobin. It must be emphasized that the carboxyhemoglobin concentration, although helpful in diagnosis, does not always correlate with the clinical findings or prognosis. Factors other than carboxyhemoglobin concentration that contribute to toxicity include length of exposure, metabolic activity, and underlying disease, especially cardiac or cerebrovascular disease. Moreover, low carboxyhemoglobin concentrations relative to the severity of poisoning may be observed if the patient was removed from the carbon monoxide-contaminated environment a significant amount of time before blood sampling.
An insidious effect of carbon monoxide poisoning is the delayed development of neuropsychiatric sequelae, which may include personality changes, motor disturbances, and memory impairment. These manifestations do not correlate with the length of exposure or with the maximum blood carboxyhemoglobin concentration.
No significant cautionary statements
1. Langman LJ, Bechtel LK, Holstege CP. Clinical toxicology. In: Rifai N, Chiu RWK, Young I, Burnham C-AD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier; 2023;454-484
2. Baselt RC. Disposition of Toxic Drugs and Chemical in Man. 12th ed. Biomedical Publications; 2020
The ABL80 OSM CO-OX analyzer is a portable, automated analyzer that measures oximetry in whole blood. Total hemoglobin oxygen saturation, carboxyhemoglobin, and methemoglobin are measured by multiwavelength spectrophotometry. Light passes through a cuvette containing hemolyzed blood sample. The specific wavelengths absorbed and their intensity generates an absorption spectrum used to calculate oximetry parameters.(Instruction manual: ABL80 FLEX CO-OX analyzer-OSM version, Radiometer Medical ApS, 01/2016)
Monday through Friday
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
82375
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
COHBB | Carbon Monoxide, B | 20563-3 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
8649 | Carbon Monoxide, B | 20563-3 |