An arterial blood gas (ABG) test measures the acidity (pH) and the levels of oxygen and CO2 in the blood from an artery. This test is used to examine how well your lungs are able to move oxygen into the blood and remove carbon dioxide from the blood.
What Is Arterial Blood Gases
As blood goes through your lungs, oxygen relocations into the blood while CO2 moves out of the blood into the lungs. An ABG test uses blood drawn from an artery, where the oxygen and CO2 levels can be measured before they get in body tissues. An ABG measures:
- Partial pressure of oxygen (PaO2). This measures the pressure of oxygen liquified in the blood and how well oxygen is able to move from the airspace of the lungs into the blood.
- Partial pressure of CO2 (PaCO2). This measures the pressure of CO2 dissolved in the blood and how well carbon dioxide has the ability to move out of the body.
- pH. The pH measures hydrogen ions (H+) in blood. The pH of blood is usually between 7.35 and 7.45. A pH of less than 7.0 is called acid and a pH higher than 7.0 is called basic (alkaline). So blood is a little standard.
- Bicarbonate (HCO3). Bicarbonate is a chemical (buffer) that keeps the pH of blood from ending up being too acidic or too fundamental.
- Oxygen material (O2CT) and oxygen saturation (O2Sat) values. O2 content measures the quantity of oxygen in the blood. Oxygen saturation measures how much of the hemoglobin at a loss blood cells is bring oxygen (O2).
Blood for an ABG test is drawn from an artery. Many other blood tests are done on a sample of blood taken from a vein, after the blood has actually already gone through the body’s tissues where the oxygen is used up and carbon dioxide is produced.
Arterial Blood Gases Values
The normal values noted here-called a recommendation range-are just a guide. These varieties vary from lab to lab and rely on the elevation above water level. Your lab might have a different variety for what’s normal. Your lab report should include the variety your laboratory uses. Likewise, your doctor will examine your outcomes based on your health and other aspects. This suggests that a value that falls outside the normal values noted here might still be normal for you or your lab.
Outcomes are normally readily available right away.
| Partial pressure of oxygen (PaO2): | Greater than 80 mm Hg (greater than 10.6 kPa) |
| Partial pressure of carbon dioxide (PaCO2): | 35-45 mm Hg (4.6-5.9 kPa) |
| pH: | 7.35-7.45 |
| Bicarbonate (HCO3): | 22-26 mEq/L (22-26 mmol/L) |
| Oxygen content (O2CT): | 15-22 mL per 100 mL of blood (6.6-9.7 mmol/L) |
| Oxygen saturation (O2Sat): | 95%-100% (0.95-1.00) |
The concentration of oxygen being breathed, called the fraction of breathed in oxygen (FiO2), is also normally reported. This is only beneficial if you are getting oxygen therapy from a tank or are on a ventilator.
Numerous conditions can change blood gas levels. Your doctor will talk with you about any unusual results that might be associated with your symptoms and previous health.
Purpose of ABG Test
An arterial blood gas (ABG) test is done to:
- Look for severe breathing problems and lung illness, such as asthma, cystic fibrosis, or chronic obstructive lung disease (COPD).
- See how well treatment for lung illness is working.
- Discover if you need extra oxygen or help with breathing (mechanical ventilation).
- Discover if you are receiving the correct amount of oxygen when you are using oxygen in the health center.
- Step the acid-base level in the blood of people who have heart failure, kidney failure, unrestrained diabetes, sleep conditions, severe infections, or after a drug overdose.
Before the test you should inform your doctor if you:
- Have had bleeding issues or take blood slimmers, such as aspirin or warfarin (Coumadin).
- Are taking any medications.
- Dislike any medicines, such as those used to numb the skin (anesthetics).
If you are on oxygen therapy, the oxygen might be turned off for 20 minutes prior to the blood test. This is called a “space air” test. If you cannot breathe without the oxygen, the oxygen will not be switched off.
Talk to your doctor about any concerns you have regarding the requirement for the test, its risks, how it will be done, or what the outcomes may imply. To assist you comprehend the significance of this test, submit the medical test details form.
Arterial Blood Gases Test Procedure
A sample of blood from an artery is normally drawn from the inside of the wrist (radial artery), but it can likewise be taken from an artery in the groin (femoral artery) or on the within the arm above the elbow crease (brachial artery). You will be seated with your arm extended and your wrist resting on a small pillow. The health professional drawing the blood might turn your restore and forth and understanding of a pulse in your wrist.
A procedure called the Allen test may be done to ensure that blood circulation to your hand is normal. An arterial blood gas (ABG) test will not be done on an arm used for dialysis or if there is an infection or inflammation in the area of the puncture site.
The health professional taking a sample of your blood will:
- Clean the needle site with alcohol. You may be provided an injection of local anesthetic to numb that area.
- Put the needle into the artery. More than one needle stick may be required.
- Enable the blood to fill the syringe. Make sure to breathe typically while your blood is being collected.
- Put a gauze pad or cotton ball over the needle site as the needle is removed.
- Put a bandage over the puncture site and apply firm pressure for 5 to 10 minutes (possibly longer if you take blood-thinning medication or have bleeding problems).
How It Feels
Collecting blood from an artery is more painful than gathering it from a vein due to the fact that the arteries are much deeper and are secured by nerves.
- Most people feel a quick, sharp pain as the needle to collect the blood sample gets in the artery. If you are provided a local anesthetic, you may feel absolutely nothing at all from the needle leak, or you might feel a brief sting or pinch as the needle goes through the skin.
- You might feel more pain if the person drawing your blood has a hard time discovering your artery, your artery is narrowed, or if you are extremely sensitive to pain.
Risks
There is long shot of a problem from having a blood sample drawn from an artery.
- You might get a small contusion at the site. You can decrease the chance of bruising by keeping pressure on the site for a minimum of 10 minutes after the needle is gotten rid of (longer if you have bleeding issues or take blood thinners).
- You might feel lightheaded, faint, woozy, or nauseated while the blood is being drawn from your artery.
- Ongoing bleeding can be an issue for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding most likely. If you have bleeding or thickening problems, or if you take blood-thinning medication, tell your doctor before your blood sample is taken.
- On unusual celebrations, the needle might harm a nerve or the artery, triggering the artery to become blocked.
- Though issues are unusual, take care with the arm or leg that had the blood draw. Do not lift or bring things for about 24 hours after you have had blood drawn from an artery.
Outcomes
An arterial blood gas (ABG) test measures the acidity (pH) and levels of oxygen and CO2 in the blood.
What Affects the Test
Reasons you may not have the ability to have the test or why the results may not be handy include the following:.
- You have a fever or an abnormally low body temperature (hypothermia).
- You have a disease that impacts how much oxygen is brought in your blood, such as severe anemia or polycythemia.
- You smoke just before the test or breathe previously owned smoke, carbon monoxide gas, or specific paint or varnish cleaners in closed or improperly ventilated areas.
What Else You Should Know About Arterial Blood Gases
- Arterial blood gas (ABG) values alone do not offer enough details to diagnose an issue. For example, they can’t tell whether low levels are brought on by lung or heart problems. Arterial blood gas values are most practical when they are evaluated with other examinations and tests.
- An ABG test is frequently provided for a person who is in the healthcare facility since of severe injury or health problem. The test can determine how well the individual’s lungs and kidneys are working and how well the body is using energy.
- An ABG test might be most useful when a person’s breathing rate is increased or decreased or when the individual has extremely high blood sugar (glucose) levels, a severe infection, or heart failure.
If numerous blood samples are needed, a thin tube (arterial catheter) may be positioned in an artery. Blood can then be collected when needed.
