In DKA, three ketone bodies are produced: BHB, acetoacetic acid, and acetone. BHB is present in the greatest concentration and accounts for approximately 75% of the three ketone bodies. During periods of ketosis, BHB increases even more than acetoacetate and acetone and has been shown to be a better indicator of ketoacidosis, including subclinical ketosis. Other names for this test include 3-hydroxybutyric acid and ketones. Testing for ketones is generally performed with nitroprusside (Acetest) tablets or reagent sticks. A 4+ reaction with serum diluted 1:1 is strongly suggestive of ketoacidosis. Nitroprusside reacts with acetoacetate and acetone but not with BHB. This is important because BHB is the predominant ketone, particularly in severe DKA. It is, therefore, possible to have a negative serum nitroprusside reaction in the presence of severe ketosis.
Normal range: 0.02 " “0.27 mmol/L.
Use
Monitoring therapy for DKA.
Investigating the differential diagnosis of any patient presenting to the emergency department with hypoglycemia, acidosis, suspected alcohol ingestion, or an unexplained increase in the AG.
In pediatric patients, the presence or absence of ketonemia/urea is an essential component in the differential diagnosis of inborn errors of metabolism.
Key parameter monitored during controlled 24-hour fasts.
Interpretation
Increased In
Alcoholic ketoacidosis
Lactic acidosis (shock, renal failure)
Liver disease
Infections
Phenformin and salicylate poisoning
Limitations
Not detectable by common tests for ketone bodies
The nitroprusside test (Acetest) may give false-negative readings because it does not detect BHB.