ABG

Medical abbreviation · Laboratory Test

ABG stands for Arterial blood gas, a laboratory test abbreviation.

Blood drawn from an artery, usually the radial artery at the wrist, to measure pH, partial pressure of carbon dioxide (PaCO2), partial pressure of oxygen (PaO2), calculated bicarbonate, base excess and oxygen saturation. Normal values are about pH 7.35 to 7.45, PaCO2 35 to 45 mmHg, PaO2 80 to 100 mmHg on room air and HCO3 22 to 26 mEq/L.

Example: ABG on 4 L nasal cannula: 7.28/68/62/31; starting BiPAP for acute-on-chronic hypercapnic respiratory failure.

Usage notes

Results are written in shorthand as pH/PaCO2/PaO2/HCO3. Clinicians often check collateral blood flow with a modified Allen test before radial puncture, although its value is debated. The sample goes in a heparinized syringe with air bubbles expelled and should be analyzed within about 30 minutes. Interpretation follows steps: acidemia or alkalemia, primary process, then compensation, for which Winter's formula predicts the expected PaCO2 in metabolic acidosis.

Related abbreviations

More laboratory test abbreviations

• 25(OH)D – 25-hydroxyvitamin D
• A1C – A1C test (hemoglobin A1c)
• ABO – ABO blood group system
• ACT – Activated clotting time
• AFB – Acid-fast bacilli
• AG – Anion gap
• Alb – Albumin
• ALC – Absolute lymphocyte count
• ALP – Alkaline phosphatase
• ALT – Alanine aminotransferase
• ANA – Antinuclear antibody
• ANC – Absolute neutrophil count

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This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.