Can artery blood gas test give accurate result if someone is already on ppis for stomach acid reduction or can it give false results in such scenario?

As a board certified internist and cardiologist you ask a great question. Certain meds can effect the acid base balance in the blood particularly if they act on the kidney. PPIs act on the stomach may rarely alter blood gas results. It should be notable that emphasizing alter as the test is still very accurate to determine oxygen, CO2 levels and acidic levels of blood.

In order to affect the pH via pCO2 and HCO3 in ABG results, one medication has to exert its effect on the kidneys or lungs because these 2 systems are instrumental in pH regulation. PPIs do not have any effect to these organs in this regard, give example, acetazolamide (diamox) can cause metabolic acidosis through the kidneys or aspirin overdose can cause respiratory alkalosis via the lungs.