What it means
The first value read on an arterial blood gasar-TEER-ee-ul BLUD GASA blood test from an artery that measures oxygen, carbon dioxide, bicarbonate and the blood's pH.Full entry . Below the normal range the blood is too acidic (acidosis); above it the blood is too alkaline (alkalosis). The PaCO2 and bicarbonate on the same result then show whether the cause is in the lungs (respiratory) or the body's chemistry (metabolic). Because the pH scale is logarithmic, small changes in the number mean large changes in acid.
At a glance
| Normal range | 7.35–7.45 |
|---|---|
| Critical range | Below 7.20 or above 7.60; each lab sets its own critical values. |
| Also written | blood pH |
Related terms
arterial blood gas
A blood test from an artery that measures oxygen, carbon dioxide, bicarbonate and the blood's pH.
metabolic acidosis
A state in which the blood is too acidic because the body has too much acid or has lost too much bicarbonate.
base excess
A value on an arterial blood gas that shows how much more or less base (buffer) the blood holds than normal.