Which method can diagnose carbon monoxide poisoning?

CO-oximetry is the correct choice for diagnosing carbon monoxide poisoning because it specifically measures different types of hemoglobin present in the blood, including oxyhemoglobin, deoxyhemoglobin, and carboxyhemoglobin. Carboxyhemoglobin is the form of hemoglobin that has carbon monoxide bound to it, and its levels are indicative of carbon monoxide exposure.

While traditional pulse oximetry can assess overall oxygen saturation, it cannot distinguish between oxyhemoglobin and carboxyhemoglobin. This means that in the case of carbon monoxide poisoning, pulse oximetry may falsely indicate normal oxygen saturation levels, which can lead to a misdiagnosis.

Capnography measures the concentration of carbon dioxide in exhaled air and is primarily used to assess ventilation rather than to detect carbon monoxide levels, making it ineffective in diagnosing carbon monoxide poisoning.

Arterial blood gas analysis provides valuable information about the acid-base status and oxygen levels in the blood, but it does not specifically quantify carboxyhemoglobin levels. Therefore, CO-oximetry remains the most accurate and reliable method for diagnosing carbon monoxide poisoning.