Analytical imprecision of lactate dehydrogenase in primary serum tubes.

BackgroundPrevious studies showed high frequency of duplicate errors of lactate dehydrogenase (LDH) measurement in primary lithium-heparin blood tubes. We hence evaluated imprecision of LDH testing and frequency of replicate errors in primary serum samples centrifuged at two different speeds.MethodsSerum samples were collected from 15 healthy subjects and centrifuged at either 1300 g or 2000 g. Serum LDH was then measured on Beckman Coulter AU5800 using the International Federation of Clinical Chemistry-recommended procedure. Complete blood cell count of top layer of serum supernatant was also performed using Advia 2120. Imprecision was calculated as coefficient of variation of 10 replicates of each serum tube, whereas the frequency of replicate errors was compared to the desirable specifications for imprecision.ResultsMean LDH values were slightly but significantly higher in serum samples centrifuged at 2000 g rather than 1300 g, whereas blood cell counts were similar. The mean imprecision of LDH was mor...