Cyanide and thiocyanate blood levels in patients with renal failure or respiratory disease.

Whole blood cyanide and plasma thiocyanate were measured by a headspace gas chromatographic method and a colorimetric method, respectively, in 16 healthy subjects, in 10 patients with respiratory disease and in 12 patients on chronic dialysis for renal failure. In healthy subjects, whole blood cyanide and plasma thiocyanate concentrations were significantly higher in smokers (1.8 +/- 0.4 mumol/l; 206 +/- 74 mumol/l) than in non-smokers (0.8 +/- 0.4 mumol/l; 74 +/- 19 mumol/l). In renal failure patients on hemodialysis, no difference was noted in cyanide levels (0.6 +/- 0.4 mumol/l), but there was a significant increase in plasma thiocyanate levels during the interdialysis period (62 +/- 24 mumol/l; 91 +/- 24 mumol/l). No difference in cyanide and thiocyanate levels of patients with respiratory disease was seen, in agreement with a weak pulmonary elimination of cyanide.