Serum lactate dehydrogenase is an important risk determinant in acute lymphocytic leukemia.

: Pretreatment serum total lactate dehydrogenase (LDH) activity was measured in 341 adult patients (greater than 15 years old) with acute lymphocytic leukemia (ALL) in order to assess its prognostic value. Failure, death during induction and remission were not related to LDH. In contrast, a negative and continuous relationship was found between LDH and relapse-free survival. Though LDH activity was significantly higher in cases with already established risk factors such as high WBC count, FAB L3 cytotype, mature B-cell phenotype, and central nervous system involvement, LDH was confirmed to be the strongest predictor of remission duration by multivariate analysis. This study provides a definitive confirmation of the negative prognostic value of LDH in adult ALL.