Serum lactate dehydrogenase isoenzyme pattern in neuroblastoma.

Total serum LDH activity and isoenzyme distribution were studied in children with neuroblastoma at the time of hospital admission. The total LDH was determined in 26 cases, and 20 (77%) of them showed elevation of its activity. On the other hand, in 9 of these 26 cases, the isoenzyme distribution was determined along with the total LDH. All 9 cases, 4 of them with normal total LDH activity, showed an abnormal isoenzyme pattern with a percentage increase in the intermediate fractions (malignant pattern). The results suggest the usefulness of the determination of serum LDH isoenzymes as a screening procedure in children with malignant tumors including neuroblastoma.