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Test Code BHYD Beta-Hydroxybutyrate, Serum

Reporting Name

Beta-Hydroxybutyrate, S

Useful For

Monitoring therapy for diabetic ketoacidosis

 

Investigating the differential diagnosis of any patient presenting to the emergency room with hypoglycemia, acidosis, suspected alcohol ingestion, or an unexplained increase in the anion gap

 

In pediatric patients, the presence or absence of ketonemia/uria is an essential component in the differential diagnosis of inborn errors of metabolism

 

Serum beta-hydroxybutyrate is a key parameter monitored during controlled 24-hour fasts

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Specimen Required


Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. Serum gel tubes should be centrifuged within 2 hours of collection.

2. Red-top tubes should be centrifuged, and the serum aliquoted into a plastic vial within 2 hours of collection.


Specimen Minimum Volume

0.25 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Frozen (preferred) 7 days
  Refrigerated  7 days

Reference Values

<0.4 mmol/L

Day(s) Performed

Monday through Sunday

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

82010

LOINC Code Information

Test ID Test Order Name Order LOINC Value
BHYD Beta-Hydroxybutyrate, S 6873-4

 

Result ID Test Result Name Result LOINC Value
BHYD Beta-Hydroxybutyrate, S 6873-4

Clinical Information

Beta-hydroxybutyrate (BHB) is 1 of 3 sources of ketone bodies. Its relative proportion in the blood (78%) is greater than the other 2 ketone bodies, acetoacetate (20%) and acetone (2%). During carbohydrate deprivation (starvation, digestive disturbances, frequent vomiting), decreased carbohydrate utilization (diabetes mellitus), glycogen storage diseases, and alkalosis, acetoacetate production increases. The increase may exceed the metabolic capacity of the peripheral tissues. As acetoacetate accumulates in the blood, a small amount is converted to acetone by spontaneous decarboxylation. The remaining and greater portion of acetoacetate is converted to BHB.

Interpretation

The beta-hydroxybutyrate (BHB)/acetoacetate ratio is typically between 3:1 and 7:1 in severe ketotic states.

 

Serum BHB increases in response to fasting, but should not exceed 0.4 mmol/L following an overnight fast (up to 12 hours).

 

In pediatric patients, a hypo- or hyper-ketotic state (with or without hypoglycemia) may suggest specific groups of metabolic disorders.

Cautions

Twenty four-hour fasting tests should not be performed in patients <2 years of age.

 

Dipstick serum ketone determination using nitroprusside reagent is often used to estimate ketone body status, but that method has inherent problems. The dipstick does not measure beta-hydroxybutyrate, the most abundant of the physiological ketone bodies; the nitroprusside reagent only reacts with acetoacetate and acetone.

Clinical Reference

1. Tietz Textbook of Clinical Chemistry. Edited by CA Burtis, ER Ashwood. Philadelphia, WB Saunders Co. 1999

2. Vassault A, Bonnefont JP, Specola N, et al: Lactate, pyruvate, and ketone bodies. In Techniques in Diagnostic Human Biochemical Genetics - A Laboratory Manual. Edited by F Hommes. New York, Wiley-Liss, 1991

3. Bonnefont JP, Specola NB, Vassault A, et al: The fasting test in paediatrics: application to the diagnosis of pathological hypo- and hyperketotic states. Eur J Pediatr 1990;150:80-85

Method Description

D-3-hydroxybutyrate in the presence of NAD is converted to acetoacetate and NADH at pH 8.5 by D-3-hydroxybutyrate dehydrogenase. At this pH the reaction is favored to the right. The NADH is converted to a colored compound using INT and Diaphorase.(Package insert: Stanbio Beta-hydroxybutyrate LiquiColor Procedure No. 2440; DN: RBR.2440.00, 4/16/2002)

Report Available

Same day/1 to 2 days

Specimen Retention Time

1 week

Reject Due To

Gross hemolysis Reject

Method Name

Photometric, B-Hydroxybutyrate Dehydrogenase (B-HBDH)