Why do we do abgs

However, you should always tell your doctor about existing medical conditions that may make you bleed more than expected. A blood gas test requires the collection of a small sample of blood. Arterial blood can be obtained from an artery in your wrist, arm, or groin, or preexisting arterial line if you are currently hospitalized. A blood gas sample can also be venous, from a vein or preexisting IV or capillary, which requires a small prick to the heel.

A healthcare provider will first sterilize the injection site with an antiseptic. You might feel a slight prick when the needle goes in. Arteries have more smooth muscle layers than veins, and some may find an arterial blood gas test more painful than a blood draw from a vein. After the needle is removed, the technician will hold pressure for a few minutes before putting a bandage over the puncture wound. The blood sample will then be analyzed by a portable machine or in an on-site laboratory.

The sample must be analyzed within 10 minutes of the procedure to ensure an accurate test result. The results of a blood gas test can help your doctor diagnose various diseases or determine how well treatments are working for certain conditions, including lung diseases.

It also shows whether or not your body is compensating for the imbalance. The normal values will have a slightly different reference range if they are from a venous or capillary sample.

Abnormal results can be signs of certain medical conditions, including the ones in the following table:. Normal and abnormal ranges can vary depending on the lab because some use different measurements or methods to analyze blood samples. You should always meet with your doctor to discuss your test results in more detail. A CO2 blood test measures the amount of carbon dioxide CO2 in your blood serum, the liquid part of your blood.

In addition, you will find tables that list commonly encountered acid-base disorders. Many methods exist to guide the interpretation of the ABG. A summary of these techniques can be found in some of the suggested articles. Step 1: Assess the internal consistency of the values using the Henderseon-Hasselbach equation:. Step 3: Is the disturbance respiratory or metabolic? What is the relationship between the direction of change in the pH and the direction of change in the PaCO 2?

For details see our conditions. This article is for Medical Professionals. In this article Blood pH Indications Procedure How to interpret arterial blood gases Other useful information from arterial blood gases Primary acid-base disturbances Mixed disorders.

Arterial Blood Gases - Indications and Interpretation In this article Blood pH Indications Procedure How to interpret arterial blood gases Other useful information from arterial blood gases Primary acid-base disturbances Mixed disorders. Blood pH Blood pH has to be maintained within a tight normal range to avoid cellular death. Allen's test Elevate the hand and make a fist for approximately 30 seconds. Apply pressure over the ulnar and the radial arteries occluding both keep the hand elevated.

Open the hand which will be blanched. Release pressure on the ulnar artery and look for perfusion of the hand this takes under eight seconds. If there is any delay then it may not be safe to perform radial artery puncture. A-a pO 2 Normal A-a pO 2 in type 2 respiratory failure. Causes of changes in anion gap Raised anion gap metabolic acidosis.

Are you protected against flu? Further reading and references. These ranges vary from lab to lab and depend upon the elevation above sea level. Your lab may have a different range for what's normal. Your lab report should contain the range your lab uses.

Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab. Greater than 80 mm Hg greater than The normal values for children may differ from the adult values listed here. The concentration of oxygen being breathed, called the fraction of inhaled oxygen FiO2 , is also usually reported.

This is only useful if you are receiving oxygen therapy from a tank or are on a ventilator. Many conditions can change blood gas levels. Your doctor will talk with you about any abnormal results that may be related to your symptoms and past health.

Reasons you may not be able to have the test or why the results may not be helpful include the following:.

Russo MD - Internal Medicine. Author: Healthwise Staff. Medical Review: E. This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use and Privacy Policy. Learn how we develop our content. To learn more about Healthwise, visit Healthwise. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.

Top of the page. Test Overview An arterial blood gas ABG test measures the acidity pH and the levels of oxygen and carbon dioxide in the blood from an artery. This measures the pressure of oxygen dissolved in the blood and how well oxygen is able to move from the airspace of the lungs into the blood. Partial pressure of carbon dioxide PaCO2. This measures the pressure of carbon dioxide dissolved in the blood and how well carbon dioxide is able to move out of the body.

The pH of blood is usually between 7.