Blood gas analysis

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Blood gas analysis is the process of measuring certain aspects of blood, which is obtained from a subject's artery. It involves puncturing a radial artery at the wrist, the femoral artery in the groin, or some other artery with a thin needle and syringe, drawing a small volume of blood. The test — referred to as an arterial blood gas (ABG) — is used to determine the pH of the blood, the partial pressure of carbon dioxide and oxygen, and the bicarbonate level among other things.

ABG testing is mainly used in pulmonology and critical care medicine to determine gas exchange across the alveolar-capillary membrane. ABG testing also has a variety of applications in other areas of medicine. Combinations of disorders can be complex and difficult to interpret, so calculators,[1][2] nomograms, and rules of thumb[3] are commonly used.

Blood gas analyzer

Blood gas analyzer

A blood gas analyzer is a machine used to aspirate the extracted arterial blood from the syringe and calculate the pH, the partial pressure of oxygen and carbon dioxide, the bicarbonate concentration. Many blood gas analyzers will also report concentrations of lactate, hemoglobin, several electrolytes, oxyhemoglobin, carboxyhemoglobin and methemoglobin. These results are usually available for interpretation within five minutes.


  1. "abg interpreter". Retrieved 2011-09-22. 
  2. "MedCalc:Acid-Base Calculator". Retrieved 2011-09-22. 
  3. Baillie JK (2008). "Simple, easily memorised 'rules of thumb' for the rapid assessment of physiological compensation for acid-base disorders". Thorax 63 (3): 289–90. doi:10.1136/thx.2007.091223. PMID 18308967.