Method for determining lactate dehydrogenase isoenzyme LD1 by stabilizing LD1 and inactivating isoenzymes LD2-LD5

摘要

The invention is drawn to a diagnostic assay for lactate dehydrogenase isoenzyme LD1 in a sample containing lactate dehydrogenase isoenzymes LD1-LD5. The disclosed assay involves the following steps: (A) adding a high molecular weight polyol, preferably polyethylene glycol having a molecular weight of 8000, to the sample to stabilize isoenzyme LD1 but not isoenzymes LD2-LD5; (B) adding an ionic amphiphile to the sample to selectively inactivate isoenzymes LD2-LD5; (C) adding sodium lactate and NAD to the sample; (D) determining LD1 by measuring a change in absorbance of the sample at 340 mm.