Official reprint from UpToDate®
www.uptodate.com ©2015 UpToDate®

Arterial blood gases

Arthur C Theodore, MD
Section Editor
Scott Manaker, MD, PhD
Deputy Editor
Geraldine Finlay, MD


An arterial blood gas (ABG) is a test that measures the oxygen tension (PaO2), carbon dioxide tension (PaCO2), acidity (pH), oxyhemoglobin saturation (SaO2), and bicarbonate (HCO3) concentration in arterial blood. Some blood gas analyzers also measure the methemoglobin, carboxyhemoglobin, and hemoglobin levels. Such information is vital when caring for patients with critical illness, respiratory, or metabolic diseases.

The sites, techniques, and complications of arterial sampling and the interpretation of ABGs are reviewed here. Interpretation of venous blood gases and detailed discussion of acid-base disturbances are discussed separately. (See "Simple and mixed acid-base disorders" and "Venous blood gases and other alternatives to arterial blood gases".)


Arterial blood gases (ABGs) are frequently used for the following:

Identification and monitoring of acid-base disturbances

Measurement of the partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2)


Subscribers log in here

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information or to purchase a personal subscription, click below on the option that best describes you:
Literature review current through: Oct 2015. | This topic last updated: Sep 22, 2015.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2015 UpToDate, Inc.
  1. AARC clinical practice guideline. Sampling for arterial blood gas analysis. American Association for Respiratory Care. Respir Care 1992; 37:913.
  2. Kohonen M, Teerenhovi O, Terho T, et al. Is the Allen test reliable enough? Eur J Cardiothorac Surg 2007; 32:902.
  3. Jarvis MA, Jarvis CL, Jones PR, Spyt TJ. Reliability of Allen's test in selection of patients for radial artery harvest. Ann Thorac Surg 2000; 70:1362.
  4. Kaye W. Invasive monitoring techniques. In: Textbook of Advanced Cardiac Life Support, American Heart Association, Dallas.
  5. Asif M, Sarkar PK. Three-digit Allen's test. Ann Thorac Surg 2007; 84:686.
  6. Guidelines for the measurement of respiratory function. Recommendations of the British Thoracic Society and the Association of Respiratory Technicians and Physiologists. Respir Med 1994; 88:165.
  7. Lightowler JV, Elliott MW. Local anaesthetic infiltration prior to arterial puncture for blood gas analysis: a survey of current practice and a randomised double blind placebo controlled trial. J R Coll Physicians Lond 1997; 31:645.
  8. Hess CE, Nichols AB, Hunt WB, Suratt PM. Pseudohypoxemia secondary to leukemia and thrombocytosis. N Engl J Med 1979; 301:361.
  9. Williams AJ. ABC of oxygen: assessing and interpreting arterial blood gases and acid-base balance. BMJ 1998; 317:1213.
  10. Severinghaus JW. Simple, accurate equations for human blood O2 dissociation computations. J Appl Physiol Respir Environ Exerc Physiol 1979; 46:599.
  11. Shapiro BA. Temperature correction of blood gas values. Respir Care Clin N Am 1995; 1:69.
  12. Hansen JE. Arterial blood gases. Clin Chest Med 1989; 10:227.
  13. Bacher A. Effects of body temperature on blood gases. Intensive Care Med 2005; 31:24.
  14. Ream AK, Reitz BA, Silverberg G. Temperature correction of PCO2 and pH in estimating acid-base status: an example of the emperor's new clothes? Anesthesiology 1982; 56:41.
  15. Bageant, RA. Variations in arterial blood gas measurements due to sampling techniques. Respir Care 1975; 20:565.
  16. Harsten A, Berg B, Inerot S, Muth L. Importance of correct handling of samples for the results of blood gas analysis. Acta Anaesthesiol Scand 1988; 32:365.
  17. Evers W, Racz GB, Levy AA. A comparative study of plastic (polypropylene) and glass syringes in blood-gas analysis. Anesth Analg 1972; 51:92.
  18. Smeenk FW, Janssen JD, Arends BJ, et al. Effects of four different methods of sampling arterial blood and storage time on gas tensions and shunt calculation in the 100% oxygen test. Eur Respir J 1997; 10:910.
  19. Hansen JE, Simmons DH. A systematic error in the determination of blood PCO2. Am Rev Respir Dis 1977; 115:1061.
  20. Mueller RG, Lang GE, Beam JM. Bubbles in samples for blood gas determinations. A potential source of error. Am J Clin Pathol 1976; 65:242.
  21. Weil MH, Rackow EC, Trevino R, et al. Difference in acid-base state between venous and arterial blood during cardiopulmonary resuscitation. N Engl J Med 1986; 315:153.
  22. Adrogué HJ, Rashad MN, Gorin AB, et al. Assessing acid-base status in circulatory failure. Differences between arterial and central venous blood. N Engl J Med 1989; 320:1312.
  23. Mathias DW, Clifford PS, Klopfenstein HS. Mixed venous blood gases are superior to arterial blood gases in assessing acid-base status and oxygenation during acute cardiac tamponade in dogs. J Clin Invest 1988; 82:833.