Cardiopulmonary: Arterial Blood Gas (ABG) Testing

What Is an Arterial Blood Gas Test?

An arterial blood gas test, also called an ABG test, measures the levels of oxygen and carbon dioxide in your blood. It also checks the acid-base balance (pH) of your blood to help show how well your lungs and kidneys are working.

Unlike most blood tests that use blood from a vein, an ABG test uses blood from an artery. Because arteries carry oxygen-rich blood from your heart and lungs, this test gives your provider important information about how well your body is getting oxygen and removing carbon dioxide.

An ABG test may measure:

• Oxygen levels in the blood
• Carbon dioxide levels in the blood
• Blood pH (acid-base balance)
• Bicarbonate (HCO3) levels

These results can help your provider evaluate breathing problems, lung disease, kidney problems, and other serious medical conditions.

At Iowa Specialty Hospitals & Clinics, we administer ABG testing to help providers better understand your breathing and overall health so they can guide the next steps in your care.

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Why Might I Need an ABG Test?

Your provider may order an arterial blood gas test to learn more about how your lungs, kidneys, and body are working. 

An ABG test may help:

• Check oxygen levels in your blood
• Measure how well your lungs remove carbon dioxide
• Evaluate breathing difficulties
• Check acid-base balance in the body
• Monitor oxygen therapy or ventilator support
• Help diagnose serious lung or kidney conditions
• Monitor certain emergency or critical health conditions

An ABG test is often used when fast, accurate information about breathing and oxygen levels is important.

What Symptoms Can an ABG Test Help Evaluate?

Your provider may recommend ABG testing if you have symptoms that may be related to a lung, breathing, or metabolic problem.

Symptoms may include:

• Shortness of breath
• Rapid breathing
• Chest discomfort
• Confusion
• Fatigue
• Dizziness
• Irregular heartbeat
• Muscle cramps or twitching
• Numbness in the hands, feet, or face

An ABG test may also be used after smoke inhalation, carbon monoxide exposure, or certain injuries that affect breathing.

Who May Need Arterial Blood Gas Testing?

Your provider may recommend an ABG test if you have a condition that affects your breathing, oxygen levels, or acid-base balance.

This may include:

• Asthma or a severe asthma attack
• Chronic obstructive pulmonary disease (COPD)
• Pneumonia or other serious lung infections
• Acute respiratory distress syndrome (ARDS)
• Acute respiratory failure
• Severe infection or sepsis
• Shock, including septic shock or hypovolemic shock
• Kidney disease or renal tubular acidosis
• Diabetic emergencies, such as diabetic ketoacidosis (DKA)
• Heart conditions, including acute heart failure or cardiac arrest
• Cystic fibrosis
• Conditions requiring oxygen therapy or ventilator support

ABG testing is also commonly used in emergency rooms, hospitals, and intensive care settings to monitor people who are seriously ill or need close monitoring of their oxygen, carbon dioxide, or acid-base levels.

What Does an ABG Test Show?

An arterial blood gas test gives your provider important information about how well your lungs and body are functioning.

The test can help answer questions such as:

• Is your body getting enough oxygen?
• Are your lungs removing carbon dioxide properly?
• Is your blood too acidic or too alkaline?
• Is oxygen therapy working?
• Is there a possible breathing or metabolic problem?
• Do you need additional testing or treatment?

The results help your provider better understand your condition and decide on the next steps for your care.

What Happens During an Arterial Blood Gas Test?

During the test, a provider takes a small blood sample from an artery, usually in your wrist. In some cases, the sample may be taken from an artery in your arm or groin. 

Before the sample is collected, your provider may check blood flow in your wrist to make sure circulation is normal.

A needle is then placed into the artery to collect the blood sample. Because arteries are deeper and more sensitive than veins, the test may feel more uncomfortable than a routine blood draw. Some patients describe a brief sharp pain or pressure during the test.

After the sample is collected, pressure is applied to the area for several minutes to help stop bleeding.

Is an ABG Test Safe?

For most people, an arterial blood gas test is safe when performed by a trained healthcare provider.

You may have mild soreness, bruising, or bleeding at the spot where the needle was placed.  Serious complications are uncommon. Very rarely, irritation or injury to the artery or nearby nerve can occur.

Your care team may ask you to avoid heavy lifting for 24 hours after the test.

How Long Does an ABG Test Take?

An arterial blood gas test usually takes about 15 to 30 minutes. 

The blood draw itself usually takes only a few minutes; however, additional time may be needed for preparation, circulation checks, and applying pressure to the site after the sample is collected.

How Should I Prepare for an ABG Test?

Your provider may give you instructions before your test.

Be sure to tell your provider about:

• Medicines you take
• Supplements you use
• Blood thinners or aspirin
• Oxygen therapy you receive

Do not stop any medicines unless your provider tells you to.

If you use an oxygen tank, your oxygen may be adjusted before the test, as long as it is safe for you. 

What Do ABG Test Results Mean?

ABG test results measure oxygen, carbon dioxide, and acid-base balance in your blood.

Abnormal results may suggest:

• A lung or breathing problem
• Kidney disease
• A metabolic disorder
• Trouble getting enough oxygen
• Difficulty removing carbon dioxide

Because many conditions can affect ABG results, your provider will review the results along with your symptoms, medical history, and any other testing.

How to Read ABG Test Results 

Your ABG results show your measured levels, the normal range for each measurement, and whether each result is within or outside that range. 

Normal ranges can vary slightly by lab, but common ABG values include:

• pH: 7.35 to 7.45
• Partial pressure of oxygen (PaO2): 75 to 100 mmHg
• Partial pressure of carbon dioxide (PaCO2): 35 to 45 mmHg
• Bicarbonate (HCO3): 22 to 26 mEq/L
• Oxygen saturation (O2Sat or SaO2): 95% to 100%

If your results are abnormal, your provider may recommend more testing, such as additional blood work or imaging, to help confirm a diagnosis and guide your care.

What Happens After the Test?

Most people can return to normal activities shortly after an arterial blood gas test.

Your provider will review your results and explain what they mean for your health. Depending on the results, you may need additional testing, treatment, oxygen therapy, or follow-up care.

A qualified healthcare provider from Iowa Specialty Hospitals & Clinics will review your results and help guide your next steps.

Get Answers About Your Breathing Health with an ABG Test

Arterial blood gas testing can help answer important questions about your lungs, kidneys, and overall health. If your provider has recommended it, Iowa Specialty Hospitals & Clinics is here to provide testing, support, and guidance for your next steps. 

Appointments may be made through MyChart. To learn more, please contact Iowa Specialty Hospitals & Clinics or visit our Locations & Hours page.