These are three in number, namely, acetoacetate (AcAc), 3-beta-hydroxybutyrate (3HB) and the third,least abundant, acetone.
Ketones are always
present in the blood in some amount and their levels increase during
fasting and prolonged exercise.
Diabetes is the most
common pathological cause leading to elevated blood ketones. In
diabetic ketoacidosis (DKA), high levels of ketones are produced in
response to low insulin levels and high levels of counter-regulatory
hormones.
Acyl CoA is produced
from break down of fatty acid, when cannot enter the Citric Acid
Cycle (Cycle is down) due to lack of insulin sensitivity, get
converted & accumulate in the form of ketone bodies.
In acute DKA, the
ketone body ratio (3HB:AcAc) rises from normal (1:1) to as high as
10:1. In response to insulin therapy, 3HB levels commonly decrease
long before AcAc levels.
The frequently
employed nitroprusside test only detects AcAc in blood and urine.
This test is inconvenient, does not assess the best indicator of
ketone body levels (3HB), provides only a semiquantitative assessment
of ketone levels and is associated with false-positive results.
Recently,
inexpensive quantitative tests of 3HB levels have become available
for use with small blood samples.
These tests offer
new options for monitoring and treating diabetes and other states
characterized by the abnormal metabolism of ketone bodies.
