Method of assessing aging of erythrocytes

A method for assessing aging of erythrocytes by using at least two types of filters having a plurality of micropores, the method comprising:

• preparing an erythrocyte suspension from a blood sample;
• allowing the erythrocyte suspension to pass through a first filter having a diameter of micropores of 5.50 to 8.00 μm, separating aged erythrocytes that do not pass through the first filter and non-aged erythrocytes that pass through the first filter, to calculate a first deformability which is an index showing the ability of erythrocytes contained in the erythrocyte suspension to pass through the first filter;
• allowing the separated non-aged erythrocyte suspension having passed through the first filter to pass through a second filter having micropores of which diameter is 3.00 to 6.00 μm, and smaller than the diameter of micropores of the first filter, separating mild aged erythrocytes that do not pass through the second filter and juvenile erythrocytes that pass through the second filter, to calculate a second deformability which is an index showing the ability of the non-aged erythrocytes contained in the non-aged erythrocyte suspension to pass through the second filter;
• and
• assessing aging of erythrocytes based on a size of the first deformability of erythrocytes contained in the erythrocyte suspension, and the second deformability of the non-aged erythrocytes.