ketone bodies in body fluid

Indications

• assessment of diabetic ketoacidosis
• verification of compliance with weight-reducing regimen

Reference interval

• serum: < 1 mg/dL (0.1 mmol/L) with overnight fast
• urine: negative, limit of detection 5-10 mg/dL (0.5-1.0 mmol/L)

Increases

• chemical interferences
  • serum
    • aspirin intoxication, IV ethanol, levodopa (Ketostix) streptozocin, insulin (prolonged, excessive)
  • urine (in vitro)
    • acetylcysteine, captopril, cysteine, dimercaprol (BAL), 8-hydroxyquinoline (preservative), levodopa, MESNA (2-mercaptoethane sulfonate), D-penicillamine, phenazopyridine, phenolphthalein, phenylketones
  • urine (in vivo)
    • aspirin intoxication, ethanol, ether anesthesia, inositol, isopropanol, metformin, methionine, nicotinic acid, phenformin, valproic acid
  • hemolysis causes discoloration of test tablets or sticks
• clinical disorders
  • diabetic ketoacidosis*, prolonged fasting, severe carbohydrate restriction with normal fat intake (weight- reducing diets), anorexia nervosa, persistent vomiting, glycogen storage diseases, branched chain ketonuria, methylmalonic aciduria, exercise in untrained subjects, pregnancy, stress, post-anesthesia
  • states with markedly increased metabolic rates
    • high fever, severe thyrotoxicosis, active acromegaly
  • excessive hormone production/administration
    • growth hormone, ACTH, glucocorticoids, hyperinsulinism, catecholamines

* in some cases of diabetes mellitus with elevated blood ketone levels, no ketone bodies appear in the urine.

Methods

• reagent strip: nitroprusside (Miles Inc. Acetotest, Ketostix, Labstix, Multistix, BMC Chemstrip)
• beta-hydroxybutyrate is NOT measured
• acetone is measured by Chemstrip & Acetest

Specimen

• serum or plasma
• cover, deliver to laboratory immediately
• refrigerate until analysis (within 5 days)
• avoid hemolysis

Interferences

False positives (urine):

• highly pigmented urine
• specimens with 8-hydroxquinoline as a preservative

Two methods may be used to distinguish false positive results caused by free sulfhydryl groups from true positives:

• add 1 drop of glacial acetic acid to the test pad
  • color is removed from false positives
• monitor reaction constantly
  • true positive develop a purple color with Acetest that continues to intensify for 60 seconds
  • false positives develop a purple color which fades within 30 seconds

More general terms

• general chemistry test

More specific terms

• ketone bodies in blood
• ketone bodies in serum/plasma
• ketone bodies in urine
• ketone bodies in urine post glucose
• ketone bodies in vitreous fluid

Additional terms

• acetoacetate in serum/plasma
• acetoacetate; beta-ketobutyrate; 3-ketobutyrate
• beta(3)-hydroxybutyrate in blood/plasma/serum

Database

• Kegg: http://www.genome.jp/dbget-bin/www_bget?