PURPOSE: To simplify diagnosis, by mixing the blood taken out of an examinee or pig with an anticoagulant and labelling an erythrocyte membrane by a spin probe and investigating the effect of halothane on the flowability of the erythrocyte membrane by an electron spin resonance method.

CONSTITUTION: Citric acid is used as an anticoagulant to collect blood under vacuum and the collected blood is quietly stirred. Next, said blood is washed with a physiological saline solution two times to prepare a suspension having a hematocrit of 20% and 16-doxylstearic acid is added to said suspension to allow the same to stand at 4°C for 15hr. Thereafter, the obtained blood is washed with a physiological saline solution two times to be again suspended so as to adjust the hematocrit to 30%. Subsequently, a solution of distilled halothane in dimethylsulfoxide is prepared to be preserved at -20°C and added to the suspension of hematocrit 30% under stirring so as to become 3mM. Then, an erythrocyte membrane is labelled by a spin probe and diagnosis is performed by an electron spin resonance apparatus by utilizing that the flowability of the erythrocyte membrane is increased. Therefore, diagnosis can be simplified.