Q: Is it absolutely necessary to have ABG (Arterial Blood Gas) for the diagnosis of DKA (diabetic ketoacidosis)?






Answer: No


Biochemically, DKA is defined and highly suspected along with clinical history as


• an increase in the serum ketones greater than 5 mEq/L,
• a blood glucose leve at least greater than 250 mg/dL
• a blood pH less than 7.3.
•  ketonuria
•  a serum bicarbonate level of 18 mEq/L or less 
•  increased anion gap,
• increased serum osmolarity and
•  increased serum uric acid


All of the above does not require ABG. Studies have shown that coefficients of variation for arterial and venous samples are similar for pH, serum bicarbonate, and potassium.

Reference:

Herrington WG, Nye HJ, Hammersley MS, Watkinson PJ. Are arterial and venous samples clinically equivalent for the estimation of pH, serum bicarbonate and potassium concentration in critically ill patients?. Diabet Med. Jan 2012;29(1):32-5