Serum LDH values in childhood acute leukemias and non-Hodgkin's lymphoma.

Serum lactate dehydrogenase activity (LDH) was examined in 66 children with acute lymphoblastic leukemia (ALL), 26 with acute non-lymphocytic leukemia (ANLL), and 116 with non-Hodgkin's lymphoma (NHL). The mean serum LDH value for the ALL and ANLL groups was not significantly different: 970 +/- 105 units/L (mean +/- standard error of the mean) and 817 +/- 161 units/L, respectively. The difference between the LDH values in patients with ALL (970 +/- 105 units/L) and NHL (551 +/- 51 units/L) was significant (P = .001). In 32% of the patients with ALL and 23% of the patients with ANLL, serum LDH values were above 1000 units/L, whereas only 13% of the cases with NHL had values above 1000 units/L. In patients with ALL the LDH levels were correlated with white blood cell counts at the time of diagnosis. In NHL, there was no difference in serum LDH levels among the various histologic subtypes. Values of LDH in stage IV NHL and in ALL were similar.