OBJECTIVETo explore the changes of blood viscosity and external thrombus in patients with silicosis and silicosis complicated with tuberculosis (TB).

METHODBlood viscosity and external thrombus were measured in 288 patients with silicosis, 178 patients with silicosis complicated by TB and 150 healthy subjects.

RESULTSBlood viscosity and external thrombus value were significantly higher in the patients of silicosis and silicosis complicated with TB than in the healthy controls, except for patients of phase I of silicosis. Blood viscosity in the silicotics increased significantly with the advance of the disease, but no significant difference in external thrombus between patients in different phases. Apparent viscosity of whole blood significantly increased in the high-shear rate (200 s(-1)) and middle-shear rate (30 s(-1)) in patients of silicosis complicated with TB than in those without complication of TB at the same phases, but not seen in the low-shear rate (5 s(-1)) and in plasma viscosity, and the length and dried weight of external thrombus increased significantly too. There was no significant difference in blood viscosity and external thrombus between patients of silicosis at phase III and those of silicosis complicated with TB at the same phase.

CONCLUSIONBlood in patients with silicosis appeared highly viscous and highly coagulant status. Blood viscosity and external thrombus value significantly increased with the advance of the disease, especially in the patients complicated with TB.