Which laboratory marker is used to confirm carbon monoxide poisoning?

Which laboratory marker is used to confirm carbon monoxide poisoning?

• A. Lactate Level
• B. PaO2
• C. Carboxyhemoglobin Level
• D. Hemoglobin A1c

Answer: (C)

Measuring carboxyhemoglobin levels with co-oximetry confirms carbon monoxide poisoning because carbon monoxide binds to hemoglobin to form carboxyhemoglobin, directly indicating CO exposure and the resulting impairment of oxygen delivery to tissues. The degree of carboxyhemoglobin correlates with severity and guides treatment decisions. Standard pulse oximetry can be misleading since it cannot distinguish carboxyhemoglobin from oxyhemoglobin and may appear falsely normal. Arterial oxygen tension (PaO2) can be normal despite tissue hypoxia because it reflects dissolved oxygen, not hemoglobin-bound oxygen. Lactate can rise with tissue hypoxia but is nonspecific to CO poisoning. Hemoglobin A1c is unrelated to acute CO exposure and reflects long-term glucose control.

Measuring carboxyhemoglobin levels with co-oximetry confirms carbon monoxide poisoning because carbon monoxide binds to hemoglobin to form carboxyhemoglobin, directly indicating CO exposure and the resulting impairment of oxygen delivery to tissues. The degree of carboxyhemoglobin correlates with severity and guides treatment decisions. Standard pulse oximetry can be misleading since it cannot distinguish carboxyhemoglobin from oxyhemoglobin and may appear falsely normal. Arterial oxygen tension (PaO2) can be normal despite tissue hypoxia because it reflects dissolved oxygen, not hemoglobin-bound oxygen. Lactate can rise with tissue hypoxia but is nonspecific to CO poisoning. Hemoglobin A1c is unrelated to acute CO exposure and reflects long-term glucose control.