30.5 Detection ofβ-Hydroxybutyrate
30.5.1 Principle
β-hydroxybutyrate forms acetoacetate on oxidation with H 2 O 2 which can be detected
with Rothera’s test.
30.5.2 Procedure
Add few drops of acetic acid in about 10 ml of urine diluted 1:1 with distilled water.
Boil for few min to remove acetone and acetoacetic acid. Add about 1 ml of H 2 O 2 ,
warm gently, and apply Rothera’s test.
Note If Rothera’s test is positive before oxidation with H 2 O 2 (with fresh urine
sample), then acetone and acetoacetic acid ketone bodies are present. If Rothera’s
test give positive result after oxidation with H 2 O 2 , thenβ-hydroxybutyrate is present
in urine.
30.6 Clinical Significance...............................
In normal conditions, the ketone bodies are produced constantly by the liver and
utilized by peripheral tissues. The normal concentration of ketone bodies in blood is
about 1–3 mg/dl, and their excretion in urine is negligible, that is, undetectable by
routine urine tests. The concentration of ketone bodies increases in the blood when
the rate of synthesis exceeds the rate of utilization, a condition named ketonemia.
The higher increase of ketone bodies in blood leads to their excretion in urine. The
excretion of ketone bodies in urine is called ketonuria. In untreated diabetes patient
and starving patient, the serum ketone body levels may reach 90 mg or above per
100 ml of serum, and urinary excretion may reach 5000 mg/24 h urine. In type I
diabetes, low insulin levels impair carbohydrate metabolism that leads to accumula-
tion of acetyl CoA and its conversion to ketone bodies. During starvation also
increased lipolysis causes overproduction of acetyl CoA which is diverted for
overproduction of ketone bodies. Both these conditions result in very high levels
of ketone bodies, lowering the blood pH, and kidneys excrete very acidic urine.
122 30 Qualitative Analysis of Ketone Bodies in Urine