Copper/zinc ratios in whole blood, plasma, and erythrocytes in pulmonary tuberculosis.

Concentrations of copper and zinc in plasma, whole blood, and erythrocytes were determined in pulmonary tuberculosis (TB) patients and controls by atomic absorption spectrophotometry. The plasma and whole blood copper/zinc ratios were markedly higher in the TB patients. Eighty-seven percent of the TB patients had plasma copper/zinc ratios above 2.00, and 94% had whole blood copper/zinc ratios above 0.20. None of the controls had plasma copper/zinc ratios above 2.00, while 24% of the controls had whole blood ratios greater than 0.20. Whole blood and plasma copper/zinc ratios appear to be more sensitive indicators of the presence of pulmonary TB than the individual copper and zinc concentrations. Patients with conditions in which copper and zinc metabolism are altered might benefit from the monitoring of copper/zinc ratios.