Stability of ketone bodies in serum in dependence on storage time and storage temperature.
The serum concentrations of beta-hydroxybutyrate and acetoacetate as well as the beta-hydroxybutyrate/acetoacetate ratio are important parameters for the differential diagnosis of certain inborn errors of metabolism. Acetoacetate, however, is an unstable compound which becomes rapidly decarboxylated. At a storage temperature of -20 degrees C about 40% of the acetoacetate is lost within 7 days and after 40 days storage at this temperature virtually all of the acetoacetate has become degraded. At -80 degrees C the decomposition of acetoacetate occurs with a much slower rate and only 15% of the initial acetoacetate is lost after 40 days storage. The rate constants for the decarboxylation reaction were found to be (6.4 +/- 2.9) * 10(-5) [min(-1)] at -20 degrees C and (0.4 +/- 0.3) * 10(-5) [min(-1)] at -80 degrees C. In contrast, beta-hydroxybutyrate is very stable during storage and hence should be used as main parameter for the evaluation of ketonemia. If determination of acetoacetate and/or of the beta-hydroxybutyrate/acetoacetate ratio is necessary, an assay immediately after collecting the serum samples is recommended. Otherwise, the serum samples should be frozen as soon as possible and stored at -80 degrees C during transport and storage.
Fritzsche
I
I
Children s Hospital, University of Leipzig, Germany.
Bührdel
P
P
Melcher
R
R
Böhme
H J
HJ
D020155:3-Hydroxybutyric Acid / Q000097:blood; D000090:Acetoacetates / Q000097:blood; D001793:Blood Preservation; D002648:Child; D015925:Cryopreservation; D005260:Female; D006801:Humans; D007657:Ketone Bodies / Q000097:blood*; D007662:Ketosis / Q000097:blood / Q000175:diagnosis; D007700:Kinetics; D008297:Male; D011933:Reagent Kits, Diagnostic / Q000592:standards; D013696:Temperature; D013997:Time Factors
D000090:Acetoacetates; D007657:Ketone Bodies; D011933:Reagent Kits, Diagnostic; C016635:acetoacetic acid; D020155:3-Hydroxybutyric Acid