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Does carbon monoxide poisoning show up in blood tests?

Carbon monoxide poisoning is a serious health concern that occurs when individuals breathe in air containing high levels of carbon monoxide (CO). This colorless and odorless gas can be produced by a variety of sources, including faulty heating systems, appliances, and vehicles. Detecting carbon monoxide poisoning early is crucial because it can cause severe health complications and even be fatal if left untreated. One of the ways to diagnose carbon monoxide poisoning is through a blood test. In this blog post, we will explore the importance of carbon monoxide blood tests, how they are conducted, and other diagnostic methods for detecting this type of poisoning.

Causes of Carbon Monoxide Poisoning

Carbon monoxide poisoning can occur when individuals inhale air that contains high levels of this gas. This can happen in various situations, such as:

Inhalation of air containing high levels of carbon monoxide

Inhaling air in enclosed spaces, such as garages, with high levels of carbon monoxide can lead to poisoning. This can happen when idling vehicles, generators, or other machinery release carbon monoxide into the air.

Exposure to faulty heating systems or appliances

Faulty heating systems or appliances can produce carbon monoxide if they are not functioning properly. This can happen with furnaces, water heaters, stoves, or any other fuel-burning devices.

Poor ventilation in enclosed spaces

Inadequate ventilation can contribute to the accumulation of carbon monoxide in enclosed spaces. This can be particularly dangerous in places like basements, attics, or poorly ventilated rooms.

Symptoms of Carbon Monoxide Poisoning

Recognizing the symptoms of carbon monoxide poisoning is crucial for early detection and timely treatment. Some common symptoms include:


A persistent headache is one of the most common initial symptoms of carbon monoxide poisoning. This headache is often described as dull and throbbing.

Nausea and vomiting

Nausea and vomiting may occur as a result of carbon monoxide exposure. These symptoms are often accompanied by stomach pain and discomfort.

Dizziness and confusion

Feeling lightheaded, dizzy, or disoriented can be a sign of carbon monoxide poisoning. Individuals may have trouble concentrating or making decisions.

Chest pain

Chest pain or discomfort may occur in some cases of carbon monoxide poisoning. This can be mistaken for a heart attack, as the symptoms can be similar.

Shortness of breath

Difficulty breathing or a sensation of breathlessness can be a symptom of carbon monoxide poisoning. This occurs because carbon monoxide inhibits the transport of oxygen in the blood.

Loss of consciousness

In severe cases, carbon monoxide poisoning can lead to a loss of consciousness or coma. This is a medical emergency and immediate treatment is required.

Importance of Blood Tests in Diagnosing Carbon Monoxide Poisoning

Blood tests play a crucial role in the diagnosis of carbon monoxide poisoning. Carbon monoxide binds to hemoglobin in red blood cells to form carboxyhemoglobin. Measuring the levels of carboxyhemoglobin in the blood can indicate the severity of the poisoning and help determine the appropriate treatment.

Carbon monoxide binds to hemoglobin in red blood cells

Hemoglobin is responsible for carrying oxygen to various parts of the body. When carbon monoxide is inhaled, it competes with oxygen to bind to hemoglobin, forming carboxyhemoglobin. This reduces the amount of oxygen that can be transported to the body’s tissues.

Blood tests can measure the levels of carboxyhemoglobin

A carbon monoxide blood test, also known as a carboxyhemoglobin test, measures the amount of carboxyhemoglobin in the blood. This is done by taking a sample of blood from a vein in the arm.

Carboxyhemoglobin levels indicate the severity of poisoning

The levels of carboxyhemoglobin in the blood can help determine the severity of carbon monoxide poisoning. Normal levels of carboxyhemoglobin are typically below 2%, but even levels as low as 10% can be indicative of poisoning.

Procedure of Carbon Monoxide Blood Tests

Performing a carbon monoxide blood test involves a few simple steps:

Collection of blood sample

A healthcare professional will collect a small sample of blood from a vein in the arm. This process is similar to a regular blood test and usually causes minimal discomfort.

Laboratory analysis of blood sample

The blood sample is then sent to a laboratory for analysis. The levels of carboxyhemoglobin are measured to determine the extent of carbon monoxide poisoning.

Interpretation of carboxyhemoglobin levels

The results of the blood test are typically reported as the percentage of carboxyhemoglobin in the blood. This percentage can help determine the severity of carbon monoxide poisoning and guide the appropriate treatment.

Other Diagnostic Methods for Carbon Monoxide Poisoning

In addition to blood tests, there are other diagnostic methods that can be used to detect carbon monoxide poisoning:

Pulse oximetry

Pulse oximetry is a non-invasive method that measures the oxygen saturation of the blood. It can provide information about the oxygen levels in the body, but it is not specific to carbon monoxide poisoning.

Arterial blood gas analysis

Arterial blood gas analysis involves taking a blood sample from an artery to measure the levels of oxygen, carbon dioxide, and other gases in the blood. This can provide valuable information about respiratory function and the presence of carbon monoxide.

Imaging techniques (e.g., CT scans, MRI)

In some cases, imaging techniques such as CT scans or MRI may be used to assess the extent of tissue damage caused by carbon monoxide poisoning. These tests can help identify any organ damage or abnormalities.

Treatment and Management of Carbon Monoxide Poisoning

Prompt treatment is essential in cases of carbon monoxide poisoning. The primary goal of treatment is to remove carbon monoxide from the body and provide adequate oxygen to the tissues. Some common treatment methods include:

Administration of oxygen therapy

Pure oxygen is administered to individuals with carbon monoxide poisoning to increase the oxygen levels in the blood. This helps to replace the carbon monoxide bound to hemoglobin with oxygen.

Hyperbaric oxygen therapy

In severe cases of carbon monoxide poisoning, hyperbaric oxygen therapy may be used. This involves breathing 100% oxygen in a pressurized chamber, which further increases oxygen levels in the blood.

Removal of the source of carbon monoxide exposure

To prevent further exposure, it is crucial to identify and remove the source of carbon monoxide. This may involve repairing or replacing faulty heating systems or appliances.

Supportive care for complications

In some cases, carbon monoxide poisoning can lead to complications such as organ damage or neurological deficits. Supportive care may be necessary to address these complications, which may include treatment from specialists in specific areas.

Prevention of Carbon Monoxide Poisoning

Taking preventive measures is essential to avoid carbon monoxide poisoning. Some key prevention strategies include:

Proper maintenance of heating systems and appliances

Regular maintenance and inspection of heating systems and appliances can help detect any potential carbon monoxide leaks or malfunctions. It is crucial to have these systems checked by professionals regularly.

Installation of carbon monoxide detectors

Carbon monoxide detectors are essential devices that can alert individuals to the presence of carbon monoxide in their surroundings. They should be installed in all areas where carbon monoxide sources are present, such as bedrooms, living rooms, and garages.

Adequate ventilation in enclosed spaces

Ensuring proper ventilation in enclosed spaces, such as garages or basements, can help prevent the buildup of carbon monoxide. Opening windows, using exhaust fans, or installing ventilation systems can improve air circulation and reduce the risk of poisoning.


Carbon monoxide poisoning is a serious health concern that can be life-threatening if not detected and treated promptly. Blood tests, such as carbon monoxide blood tests, play a crucial role in diagnosing this type of poisoning by measuring the levels of carboxyhemoglobin in the blood. Prompt treatment, along with preventive measures, such as proper maintenance of heating systems, installation of carbon monoxide detectors, and adequate ventilation, can help prevent carbon monoxide poisoning and ensure the safety of individuals in various settings. Being aware of the causes, symptoms, diagnostic methods, and treatment options for carbon monoxide poisoning can save lives and promote overall health and well-being.


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