Serum lactic dehydrogenase and isoenzyme changes in clinical cancer

Total LDH and LDH isoenzyme values were measured in serum collected from patients at the time of hospital admission. Changes in isoenzyme values were not necessarily found to depend upon elevated total serum LDH levels. Many patients with normal levels of serum LDH had abnormal isoenzyme patterns usually related to a disease process. A large percentage of patients with neoplastic disease had statistically increased LDH 5 values. Many other patients with either acute and/or chronic disease failed to reflect changes in the isoenzyme values.