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PEHSU Factsheet: Carbon Monoxide Poisoning in Children and Pregnant People > How to Diagnose and Evaluate CO Poisoning?

How to Diagnose and Evaluate CO Poisoning?

posted on Jan 31, 2022

In order to distinguish CO poisoning from other indoor air pollutants, thorough history-taking is critical. Important points to identify include living situation (age of the house, use of flame-based heating elements (e.g. oil, propane, gasoline, natural gas) or gas-fired electricity generators) and others in the household having a similar constellation of symptoms.

Diagnosis is based on a suggestive history and physical findings coupled with confirmatory testing. Patients with significant COHgb levels can have normal readings on a regular pulse oximeter. Confirmatory methods include direct measurement of blood COHgb or measurement of COHgb using a transcutaneous co-oximeter capable of specifically measuring COHgb.9,28 Normal COHgb levels in non-smokers can range from 1-2%, while in cigarette smokers, they can range from 5-10%.23,25 Patients should be examined for other conditions, including smoke inhalation, trauma, medical illness, or intoxication. A neurological exam should include an assessment of age-appropriate cognitive function.