Breadcrumb
- Home
- Tests, Treatments & Medications
- Medical Tests
- Arterial Blood Gases
Content Map Terms
Tests, Treatments & Medications Categories
-
Medications
- Immunization, Inactivated influenza
- Anthrax Vaccine
- Diphtheria, Pertussis, and Tetanus Vaccines
- Haemophilus Influenzae Type B (Hib) Vaccine
- Hepatitis A Vaccine
- Hepatitis B Vaccine
- Herpes-Zoster Vaccine for Shingles
- Human Papillomavirus (HPV) Vaccine
- Measles, Mumps, and Rubella Vaccine
- Meningococcal Vaccine
- Pneumococcal Vaccines
- Polio Vaccine
- Rotavirus Vaccine
- Varicella-Zoster Vaccine for Chickenpox
- Weight-Loss Medicines
- Non-Prescription Products for Weight Loss
- Obesity: Should I Take Weight-Loss Medicine?
-
Medical Tests
- Abdominal Ultrasound
- Abdominal X-Ray
- Adrenocorticotropic Hormone
- Alanine Aminotransferase (ALT)
- Albumin Urine Test
- Aldosterone in Blood
- Aldosterone in Urine
- Alkaline Phosphatase
- Allergy Tests
- Alpha-Fetoprotein (AFP) in Blood
- Ambulatory Electrocardiogram
- Ammonia
- Amniocentesis
- Amylase
- Angiogram
- Angiogram of the Head and Neck
- Angiogram of the Lung
- Antinuclear Antibodies (ANA)
- Antisperm Antibody Test
- Antithyroid Antibody Tests
- Arterial Blood Gases
- Arthrogram (Joint X-Ray)
- Arthroscopy
- Aspartate Aminotransferase (AST)
- Autoimmune Disease Tests
- Autopsy
- Barium Enema
- Bilirubin
- Biophysical Profile (BPP)
- Biopsy of Genital Warts
- Bladder Stress Test and Bonney Test for Urinary Incontinence in Women
- Blood Alcohol
- Blood Culture
- Blood Glucose
- Blood Type Test
- Blood Urea Nitrogen
- Body Temperature
- Bone Biopsy
- Bone Density
- Bone Marrow Aspiration and Biopsy
- Bone Scan
- Bowel Transit Time
- Brain Natriuretic Peptide (BNP) Test
- Breast Biopsy
- Breast Cancer (BRCA) Gene Test
- Breast Ultrasound
- Bronchoscopy
- C-Peptide
- C-Reactive Protein (CRP)
- Calcium (Ca) in Blood
- Calcium (Ca) in Urine
- Cancer Antigen 125 (CA-125)
- Carbon Dioxide
- Carbon Monoxide (CO)
- Carcinoembryonic Antigen (CEA)
- Cardiac Blood Pool Scan
- Cardiac Catheterization
- Cardiac Enzyme Studies
- Cardiac Perfusion Scan
- Catecholamines in Blood
- Catecholamines in Urine
- CD4+ Count
- Celiac Disease Antibodies
- Cell-Free Fetal DNA Test
- Chemistry Screen
- Chest X-Ray
- Chlamydia Tests
- Chloride (Cl)
- Cholesterol and Triglycerides Tests
- Chorionic Villus Sampling (CVS)
- Clinical Breast Examination
- Clostridium Difficile Toxins
- Cold Agglutinins
- Colonoscopy
- Colposcopy and Cervical Biopsy
- Complete Blood Count (CBC)
- Computed Tomography (CT) Scan of the Body
- Computed Tomography (CT) Scan of the Head and Face
- Computed Tomography (CT) Scan of the Spine
- Computed Tomography Angiogram
- Contraction Stress Test
- Coombs Antibody Test
- Coronary Calcium Scan
- Cortisol in Blood
- Cortisol in Urine
- Cranial Ultrasound
- Creatine Kinase
- Creatinine and Creatinine Clearance
- Cystometry
- Cystoscopy
- Cystourethrogram
- D-Dimer Test
- D-Xylose Absorption Test
- DHEA-S Test
- Dental X-Rays
- Digital Rectal Examination (DRE)
- Doppler Ultrasound
- Ear Examination
- Echocardiogram
- Electrocardiogram
- Electroencephalogram (EEG)
- Electromyogram (EMG) and Nerve Conduction Studies
- Electronystagmogram (ENG)
- Electrophysiology Study
- Electrophysiology Tests for the Eyes
- Endometrial Biopsy
- Endoscopic Retrograde Cholangiopancreatogram (ERCP)
- Endoscopic Sinus Examination for Sinusitis
- Esophagus Tests
- Evoked Potential Test for Multiple Sclerosis
- Exercise Electrocardiogram
- Extremity X-Ray
- Facial X-Ray
- Ferritin
- Fertility Awareness
- Fetal Blood Sampling (FBS) for Rh Sensitization During Pregnancy
- Fetal Ultrasound
- Folic Acid Test
- Galactosemia Test
- Gallbladder Scan
- Gallium Scan
- Gastrin
- Genetic Test
- Glycohemoglobin
- Gonioscopy
- Gonorrhea Test
- Growth Hormone
- HIV Viral Load Measurement
- Hair Analysis
- Hearing Tests
- Heart Catheterization for Congenital Heart Defects
- Helicobacter Pylori Tests
- Hemochromatosis Gene Test
- Hemoglobin Electrophoresis
- Hepatitis A Virus Test
- Hepatitis B Virus Tests
- Hepatitis C Virus Tests
- Herpes Tests
- High-Sensitivity C-Reactive Protein
- Home Blood Glucose Test
- Home Blood Pressure Test
- Home Ear Examination
- Home Lung Function Test
- Home Pregnancy Tests
- Homocysteine
- Hormone Inhibin A
- Human Chorionic Gonadotropin (HCG)
- Human Immunodeficiency Virus (HIV) Test
- Human Papillomavirus (HPV) Test
- Hysterosalpingogram
- Hysteroscopy
- Immunoglobulins
- Intravenous Pyelogram (IVP)
- Iron (Fe)
- Joint Fluid Analysis
- KOH Preparation
- Karyotype Test
- Ketones
- Kidney Biopsy
- Kidney Scan
- Kidney Stone Analysis
- Lactic Acid Dehydrogenase (LDH)
- Lactic Acid
- Laparoscopy
- Laryngoscopy
- Lead
- Lipase
- Liver Biopsy
- Liver Function Tests
- Liver and Spleen Scan
- Lumbar Puncture
- Lung Biopsy
- Lung Cancer Screening: Low-Dose CT Scan
- Lung Function Tests
- Lung VQ Scan
- Lyme Disease Test
- Lymph Node Biopsy
- Magnesium (Mg)
- Magnetic Resonance Angiogram (MRA)
- Magnetic Resonance Imaging (MRI) of the Abdomen
- Magnetic Resonance Imaging (MRI) of the Breast
- Magnetic Resonance Imaging (MRI) of the Head
- Magnetic Resonance Imaging (MRI) of the Knee
- Magnetic Resonance Imaging (MRI) of the Shoulder
- Magnetic Resonance Imaging (MRI) of the Spine
- Magnetic Resonance Imaging (MRI)
- Mammogram
- Mediastinoscopy
- Medicine Levels in Blood
- Mental Health Assessment
- Mononucleosis Tests
- Myelogram
- Myoglobin
- Needle Puncture and Aspiration of Sinus Contents for Sinusitis
- Neurological Examination for Multiple Sclerosis
- Neuropsychological Tests
- Nuchal Translucency Screening Test
- Ophthalmoscopy
- Oral Glucose Tolerance Test
- Overnight Dexamethasone Suppression Test
- Pap Test
- Paracentesis
- Parathyroid Hormone
- Partial Thromboplastin Time
- Pelvic Examination
- Pelvic Ultrasound
- Pericardial Drainage
- Perimetry Test for Glaucoma
- Phenylketonuria (PKU) Test
- Phosphate in Blood
- Phosphate in Urine
- Positron Emission Tomography (PET)
- Potassium (K) in Blood
- Potassium (K) in Urine
- Prealbumin Blood Test
- Prolactin
- Prostate Biopsy
- Prostate-Specific Antigen (PSA)
- Prothrombin Time and INR
- Pulse Measurement
- Radioactive Iodine Uptake Test
- Rapid Strep Test for Strep Throat
- Renin Assay
- Reticulocyte Count
- Retinal Imaging
- Retrograde Pyelogram for Kidney Stones
- Rheumatoid Factor (RF)
- Rubella Test
- Salivary Gland Scan
- Sedimentation Rate
- Seizure Medicine Levels in Blood
- Self-Examination for Dental Plaque
- Semen Analysis
- Sentinel Lymph Node Biopsy
- Serum Osmolality
- Serum Protein Electrophoresis (SPEP)
- Sickle Cell Test
- Sigmoidoscopy
- Single Photon Emission Computed Tomography (SPECT)
- Skin Biopsy
- Skin and Wound Cultures
- Skull X-Ray
- Sleep Studies
- Slit Lamp Examination
- Sodium (Na) in Blood
- Sodium (Na) in Urine
- Sonohysterogram
- Spinal X-Ray
- Sputum Culture
- Sputum Cytology
- Stool Analysis
- Stool Culture
- Stool Tests for Colorectal Cancer
- Swallowing Study
- Sweat Test
- Syphilis Tests
- Tay-Sachs Test
- Testicular Biopsy
- Testicular Examination and Testicular Self-Examination
- Testicular Scan
- Testicular Ultrasound
- Testosterone
- Tests for Bacterial Vaginosis
- Tests for Erection Problems
- Thick and Thin Blood Smears for Malaria
- Thoracentesis
- Throat Culture
- Thyroid Biopsy
- Thyroid Hormone Tests
- Thyroid Scan
- Thyroid and Parathyroid Ultrasound
- Thyroid-Stimulating Hormone (TSH)
- Tissue Type Test
- Tonometry
- Total Serum Protein
- Toxicology Tests
- Toxoplasmosis Test
- Tuberculin Skin Test
- Tympanocentesis for Ear Infections
- Tympanometry in Ear Infections
- Upper Gastrointestinal (UGI) Series
- Upper Gastrointestinal Endoscopy
- Uric Acid in Blood
- Uric Acid in Urine
- Urine Culture
- Urine Test
- Urodynamic Tests for Urinary Incontinence
- Vaginal Examination for Preterm Labour
- Vaginal Self-Examination (VSE)
- Vaginal Wet Mount
- Viral Tests
- Vision Tests
- Vitamin B12 Test
- Vitamin D Test
-
Surgery
- Achilles Tendon Rupture: Should I Have Surgery?
- ACL Injury: Should I Have Knee Surgery?
- Blood Transfusions: Should I Bank Blood Before Surgery?
- Bunions: Should I Have Surgery?
- Carpal Tunnel Syndrome: Should I Have Surgery?
- Cataracts: Should I Have Surgery?
- Dupuytren's Disease: Should I Have Hand Surgery?
- Ear Problems: Should My Child Be Treated for Fluid Buildup in the Middle Ear?
- Endometriosis: Should I Have a Hysterectomy and Oophorectomy?
- Enlarged Prostate: Should I Have Surgery?
- Gallstones: Should I Have Gallbladder Surgery?
- GERD: Which Treatment Should I Use?
- Hammer, Claw, or Mallet Toe: Should I Have Surgery?
- Coronary Artery Disease: Should I Have Bypass Surgery?
- Hysterectomy: Should I Also Have My Ovaries Removed?
- Inguinal Hernia: Should I Have Surgery Now, or Should I Wait?
- Lumbar Herniated Disc: Should I Have Surgery?
- Lumbar Spinal Stenosis: Should I Have Surgery?
- Meniscus Tear: Should I Have Surgery?
- Nearsightedness: Should I Have Laser Surgery?
- Pelvic Organ Prolapse: Should I Have Surgery?
- Peripheral Arterial Disease: Should I Have Surgery?
- Plantar Fasciitis: Should I Have Surgery for Heel Pain?
- Rotator Cuff Problems: Should I Have Surgery?
- Scoliosis: Should My Child Have Surgery?
- Sinusitis: Should I Have Surgery?
- Sleep Apnea: Should I Have Surgery?
- Stress Incontinence in Women: Should I Have Surgery?
- Tennis Elbow: Should I Have Surgery?
- Temporomandibular Disorder: Should I Have Surgery for Jaw Pain?
- Tonsillitis: Should My Child Have a Tonsillectomy?
- Ulcerative Colitis: Should I Have Surgery?
- Umbilical Hernia: Should I Have Surgery?
- Umbilical Hernia: Should My Child Have Surgery?
- Uterine Fibroids: Should I Have Surgery?
- Varicose Veins: Should I Have a Surgical Procedure?
- Wisdom Teeth: Should I Have My Wisdom Teeth Removed?
-
Treatments
- Bedwetting: Should My Child See a Doctor?
- Complementary Medicine: Should I Use Complementary Medicine?
- Advance Care Planning: Should I Receive CPR and Life Support?
- Advance Care Planning: Should I Stop Treatment That Prolongs My Life?
- Hearing Loss: Should I Get Hearing Aids?
- Atrial Fibrillation: Should I Have Catheter Ablation?
- Hemorrhoids: Which Treatment Should I Use?
- Kidney Failure: What Type of Dialysis Should I Have?
- Low Back Pain: Should I Try Epidural Steroid Shots?
- Obesity: Should I Use a Diet Plan to Lose Weight?
- Testicular Cancer: Which Treatment Should I Have for Stage I Non-Seminoma Testicular Cancer After My Surgery?
- Testicular Cancer: Which Treatment Should I Have for Stage I Seminoma Testicular Cancer After My Surgery?
- Warts: Should I Treat Warts?
- First Aid
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 test is used to check how well your lungs are able to move oxygen into the blood and remove carbon dioxide from the blood.
As blood passes through your lungs, oxygen moves into the blood while carbon dioxide moves out of the blood into the lungs. An ABG test uses blood drawn from an artery, where the oxygen and carbon dioxide levels can be measured before they enter body tissues. An ABG measures:
- Partial pressure of oxygen (PaO2). 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.
- 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 greater than 7.0 is called basic (alkaline). So blood is slightly basic.
- Bicarbonate (HCO3). Bicarbonate is a chemical (buffer) that keeps the pH of blood from becoming too acidic or too basic.
- Oxygen content (O2CT) and oxygen saturation (O2Sat) values. O2 content measures the amount of oxygen in the blood. Oxygen saturation measures how much of the hemoglobin in the red blood cells is carrying oxygen (O2).
Blood for an ABG test is taken from an artery. Most other blood tests are done on a sample of blood taken from a vein, after the blood has already passed through the body's tissues where the oxygen is used up and carbon dioxide is produced.
Why It Is Done
An arterial blood gas (ABG) test is done to:
- Check for severe breathing problems and lung diseases, such as asthma, cystic fibrosis, or chronic obstructive pulmonary disease (COPD).
- See how well treatment for lung diseases is working.
- Find out if you need extra oxygen or help with breathing (mechanical ventilation).
- Find out if you are receiving the right amount of oxygen when you are using oxygen in the hospital.
- Measure the acid-base level in the blood of people who have heart failure, kidney failure, uncontrolled diabetes, sleep disorders, severe infections, or after a drug overdose.
How To Prepare
Tell your doctor if you:
- Take a blood thinner, or if you have had bleeding problems.
- Are taking any medicines.
- Are allergic to any medicines, such as those used to numb the skin (anesthetics).
If you are on oxygen therapy, the oxygen may be turned off for 20 minutes before the blood test. This is called a "room air" test. If you can't breathe without the oxygen, the oxygen will not be turned off.
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results may mean. To help you understand the importance of this test, fill out the medical test information form .
How It Is Done
A sample of blood from an artery is usually taken from the inside of the wrist (radial artery), but it can also be taken from an artery in the groin (femoral artery) or on the inside of 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 may rotate your hand back and forth and feel for a pulse in your wrist.
A procedure called the Allen test may be done to ensure that blood flow 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 given an injection of local anesthetic to numb that area.
- Put the needle into the artery. More than one needle stick may be needed.
- Allow the blood to fill the syringe. Be sure to breathe normally 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 medicine or have bleeding problems).
How It Feels
Collecting blood from an artery is more painful than collecting it from a vein because the arteries are deeper and are protected by nerves.
- Most people feel a brief, sharp pain as the needle to collect the blood sample enters the artery. If you are given a local anesthetic, you may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes through the skin.
- You may feel more pain if the person drawing your blood has a hard time finding your artery, your artery is narrowed, or if you are very sensitive to pain.
Risks
There is little chance of a problem from having a blood sample taken from an artery.
- You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for at least 10 minutes after the needle is removed (longer if you have bleeding problems or take blood thinners).
- You may feel light-headed, faint, dizzy, or nauseated while the blood is being drawn from your artery.
- On rare occasions, the needle may damage a nerve or the artery, causing the artery to become blocked.
Though problems are rare, be careful with the arm or leg that had the blood draw. Do not lift or carry objects for about 24 hours after you have had blood drawn from an artery.
Results
An arterial blood gas (ABG) test measures the acidity (pH) and levels of oxygen and carbon dioxide in the blood.
Normal
The normal values listed here—called a reference range—are just a guide. 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.
Results are usually 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): |
|
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 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.
What Affects the Test
Reasons you may not be able to have the test or why the results may not be helpful include the following:
- You have a fever or an abnormally low body temperature (hypothermia).
- You have a disease that affects how much oxygen is carried in your blood, such as severe anemia or polycythemia.
- You smoke just before the test or breathe second-hand smoke, carbon monoxide, or certain paint or varnish removers in closed or poorly ventilated areas.
What To Think About
- Arterial blood gas (ABG) values alone don't provide enough information to diagnose a problem. For example, they can't tell whether low levels are caused by lung or heart problems. Arterial blood gas values are most helpful when they are reviewed with other examinations and tests.
- An ABG test is often done for a person who is in the hospital because of severe injury or illness. The test can measure how well the person's lungs and kidneys are working and how well the body is using energy.
- An ABG test may be most useful when a person's breathing rate is increased or decreased or when the person has very high blood sugar (glucose) levels, a severe infection, or heart failure.
- If several blood samples are needed, a thin tube (arterial catheter) may be placed in an artery. Blood can then be collected when needed.
Related Information
References
Citations
- Fischbach F, Dunning MB III (2015). A Manual of Laboratory and Diagnostic Tests, 9th ed. Philadelphia: Wolters Kluwer Health.
Other Works Consulted
- Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
- Davis MD, et al. (2013). AARC clinical practice guideline: Blood gas analysis and hemoximetry: 2013. Respiratory Care, 58(10): 1694–1703. DOI: 10.4187/respcare.02786. Accessed March 12, 2014.
- Pagana KD, Pagana TJ (2010). Mosby's Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.
Credits
Current as of:
February 24, 2020
Author: Healthwise Staff
Medical Review:
E. Gregory Thompson MD - Internal Medicine
Anne C. Poinier MD - Internal Medicine
Adam Husney MD - Family Medicine
Robert L. Cowie MB, FCP(SA), MD, MSc, MFOM - Pulmonology
Elizabeth T. Russo MD - Internal Medicine
Current as of: February 24, 2020
Author: Healthwise Staff
Medical Review:E. Gregory Thompson MD - Internal Medicine & Anne C. Poinier MD - Internal Medicine & Adam Husney MD - Family Medicine & Robert L. Cowie MB, FCP(SA), MD, MSc, MFOM - Pulmonology & Elizabeth T. Russo MD - Internal Medicine
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.
Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
HealthLinkBC Files
HealthLinkBC Files are easy-to-understand fact sheets on a range of public health and safety topics including disease prevention and immunizations.
Find Services and Resources
If you are looking for health services in your community, you can use the HealthLinkBC Directory to find hospitals, clinics, and other resources.