Diagnostic and prognostic value of very high serum lactate dehydrogenase in admitted medical patients.

BACKGROUND Serum lactate dehydrogenase (LDH) is elevated in various diseases. OBJECTIVES To analyze serum LDH as a distinguishing clinical biomarker and as a predictor of in-hospital outcome in admitted medical patients. METHODS We analyzed a cohort of all 158 patients with very high isolated LDH (LDH > or = 800 IU/ml without concomitant elevations of alanine aminotransferase and aspartate aminotransferase) admitted to our internal medicine department during a 3 year period. Epidemiologic and clinical data, as well as the final diagnosis and outcome were recorded and compared with those of a cohort of all 188 consecutive control patients. RESULTS Very high isolated LDH was a distinguishing biomarker for the presence of cancer (27% vs. 4% in the LDH group and controls respectively, P < 0.0001), liver metastases (14% vs. 3%, P < 0.0001), hematologic malignancies (5% vs. 0%, P = 0.00019), and infection (57% vs. 28%, P < 0.0001). Very high isolated LDH was a marker for severe prognosis, associated with more admission days (9.3 vs. 4.1, P < 0.0001), significantly more in-hospital major complications, and high mortality rate (26.6% vs. 4.3%, P < 0.0001). Finally, very high isolated LDH was found in a multivariate regression analysis to be an independent predictor of mortality. CONCLUSIONS The presence of very high isolated LDH warrants thorough investigation for the presence of severe underlying disease, mostly metastatic cancer, hematologic malignancies, and infection. Moreover, it is a marker for major in-hospital complications and is an independent predictor of mortality in admitted medical patients. lactate dehydrogenase (LDH), cancer, internal medicine