Pleural effusions and sera from patients with benign or malignant diseases- Copper, zinc, and laboratory parameters

In pleural effusions and sera from 66 patients copper and zinc were quantif ied by inductively coupled argon plasma-mass spectrometry after mineralizat ions in a closed-pressurized microwave unit with a mixture of concentrated nitric acid and 30% hydrogen peroxide. Total protein, pH, leukocyte count, lactate dehydrogenase, glucose, C-reactive protein, ceruloplasmin, and alph a (1)-antitrypsin were determined in many of the effusions. All but four ef fusions had concentrations of copper (range 58-1720 mug/kg) and zinc (range 27-1001 mug/kg) that were lower than the concentrations in the correspondi ng sera. Very high concentrations of zinc (1930-6470 mug/kg) were character istic for thoracic empyemata. In the scatterplots of serum copper versus ef fusion copper, serum zinc versus effusion zinc, and serum copper/effusion c opper versus serum zinc/effusion zinc no clearly delineated regions were no ticeably useful for identifying malignant effusions. Similar plots of the c oncentrations of copper or zinc versus the eight clinical laboratory parame ters or plots of clinical parameter versus clinical parameter failed to be of diagnostic value. Statistically highly significant correlations (p less than or equal to 0.05, n > 45, r(2) > 0.25) were observed for 9 of 28 pairs of the clinical parameters, for total protein and copper in the effusions and zinc in the effusions and for ceruloplasmin and copper in the effusions . Among the patients suffering from benign or malignant effusions, 52% had zinc concentrations in the sera below the low limit of the normal range (60 0 mug/kg). Supplementation of such patients with zinc should be considered.