Lactic Dehydrogenase Activity of Effusion Fluids as an Aid to Differential Diagnosis

Abstract

THE DETECTION of malignancy in patients with effusions of unknown etiology often presents a difficult challenge. Wroblewski and Wroblewski,¹attempting to facilitate such diagnosis, found that the presence or absence of malignancy was indicated by the relative activities of the enzyme lactic dehydrogenase in the patient's serum and effusion fluid. Where effusion was of malignant origin, the lactic dehydrogenase (LDH) activity of the effusion fluid was higher than that of the simultaneously drawn serum. The reverse was true for effusions of non-malignant etiology. These results were confirmed by three later reports of F. Wroblewski^2-4and by Torregrosa.⁵ Although LDH activity was generally higher in effusion fluids accompanied by malignancy, Wroblewski and Wroblewski¹did not note a direct relationship between malignancy and the effusion fluid LDH activity per se. Their hypothesis, that effusions gained LDH from adjacent malignant cells, suggested that such a relationship might exist. A