Determination of D-lactate by enzymatic methods in biological fluids: study of interferences.
Analysis of nondeproteinized samples with an enzymatic method to determine D-lactate indicated interferences. The presence of L-lactate dehydrogenase (LD) and L-lactate in the sample led to underestimation of D-lactate content when a sample blank was processed and overestimation when it was omitted. We proved that this interference is not due to lack of D-LD stereospecificity. Moreover, assessment of D-LD and L-LD KM for NAD+ allowed us to rule out the different affinities for this coenzyme as a cause of the interference. Our results underline the importance of deproteinizing samples for D-lactate analysis when enzymatic methods are used. The ultrafiltration procedure we propose is convenient and shows acceptable mean recovery (108%) and good imprecision (within-run CV = 4.2% and 3.0% for D-lactate at 31 and 107 mumol/L, respectively; between-run CVs were 7.3% at 49 mumol/L D-lactate and 3.1% at 115 mumol/L D-lactate).
Martí
R
R
Servei de Bioquimica, Hospital General Universitari Vall d'Hebron, Barcelona, Spain.
Varela
E
E
Segura
R M
RM
Alegre
J
J
Suriñach
J M
JM
Pascual
C
C
D001826:Body Fluids / Q000378:metabolism; D006440:Hemofiltration; D006801:Humans; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000097:blood / Q000378:metabolism*; D019344:Lactic Acid / Q000097:blood / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D010994:Pleura / Q000378:metabolism; D013053:Spectrophotometry / Q000379:methods; D013237:Stereoisomerism
D009243:NAD; D019344:Lactic Acid; D007770:L-Lactate Dehydrogenase