Lactate dehydrogenase (LD) activity determinations in serum are being used, since years, for diagnosing many diseases involving heart, erythrocytes, liver and for detecting tumours. The serum contains in variable proportions five LD isoenzymes, formed from monomeric polypeptides B and A. The B4 isoenzyme - LD1 - is more abundant in the cells of heart muscle, kidney, brain and in erythrocytes. The LD1 determination in serum is particularly useful in the biochemical diagnosis of myocardial infarction.
The objective of the project is to work both on a reliable method for the determination of the catalytic concentration of LD and on a reference enzyme preparation enabling the transfer of that method. The LD1 isoenzyme will be purified from human erythrocytes.
A preliminary study has shown that a stable LD1 could be prepared. A batch of about 1500 samples is available for certification. A first intercomparison with 11 laboratories has been performed in 1989 with the following results : between-laboratory CV = 13.9% and within-laboratory CV = 4.2% on average. The followed method was that recommended by the French Society for Clinical Biology (SFBC). After several points of the methodology have been assessed (e.g. linearity of the reaction and purity of the reagents), much improvement was recorded. 8 participants will be involved in the value assignment campaign (due in 1992) with the SFBC method. Certification is expected in 1993.
Funding SchemeCSC - Cost-sharing contracts
EN6 3QG Potters Bar