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What Is an Arterial Blood Sample?

Medically Reviewed on 1/28/2021

How do medical professionals collect an arterial blood sample?

An arterial blood sample analyzes the concentration of certain gases dissolved in the blood.

There are three main types of blood vessels in the body, namely, arteries, veins, and capillaries. Arteries are the large blood vessels carrying oxygenated blood from the heart to body tissues. The distribution of the arteries in the body is like a tree with branches. The common trunk of the arterial tree is formed by the aorta, whereas the smallest branches extend to the peripheral parts of the body and organs. An arterial blood sample is a blood sample collected from the peripheral artery.

The arterial blood sample is mainly collected to analyze the concentration of certain gases dissolved in the blood. This procedure is called an arterial blood gas analysis (ABG). The blood sample for ABG can be obtained in two ways, namely, through a catheter placed in an artery and by using a needle and syringe to puncture an artery.

ABG analysis is a popular procedure. It can be done at the patient’s bedside. The test involves a rapid analysis of the parameters. Thus, it is an important tool used by doctors to plan and modify the treatment of their patients. It may be especially useful for patients who are critically ill, such as patients with heart diseases, kidney diseases, or uncontrolled diabetes. The test can reveal whether the exchange of gases is occurring properly in the body. This can reflect any abnormalities in the lungs, heart, kidney, or metabolism.

What does an arterial blood gas analysis measure?

Arterial blood gas (ABG) analysis can measure the following:

  • The concentration of oxygen and carbon dioxide gases in the blood
  • The pH of the blood that reveals how acidic or alkaline the blood is

Why do medical professionals perform an arterial blood gas analysis?

The blood carries dissolved gases such as oxygen and carbon dioxide. The oxygen enters the blood when it travels through the lungs, whereas the waste gas from the tissues (carbon dioxide) is removed from the blood. The balance of these gases also influences the pH of the blood. Thus, arterial blood gas (ABG) analysis may be done to diagnose various health conditions that may affect the lungs, heart, and kidneys. These medical conditions may manifest as a change in oxygen saturation, carbon dioxide levels, or pH of the blood.

ABG analysis can be used for diagnosing the following:

  • Diseases of the lungs such as asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis
  • Kidney failure
  • Diabetes complications such as diabetic ketoacidosis (DKA) and hyperglycemic hyperosmolar state (HHS)
  • Severe infections or septicemia
  • Drug overdose
  • Poisoning
  • Heart failure
  • Hemorrhage
  • Shock

Arterial blood sampling may also be performed to observe the patient’s response to the treatment. It also tells the doctor whether the patient needs supplemental oxygen or other aided support for breathing.

What are the complications of arterial blood sampling?

Arterial blood sampling is a relatively safe procedure with a low risk of complications. Some complications that may occur as a result of arterial blood sampling include

  • bleeding from the arterial puncture site,
  • bruising at the site of sample collection,
  • infection,
  • pain and tenderness around the site of sample collection, and
  • swelling the site of sample collection.


Asthma is a chronic respiratory disease.
See Answer

Medically Reviewed on 1/28/2021


Danckers, Mauricio. “Arterial Blood Gas Sampling.” May 8, 2020. .

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