The invention relates to the technical field of medical apparatus and instruments, in particular to a quantitative sample
injector for
blood separation which comprises a sample suction tube of which atop part is provided with an accommodating space, a filter membrane which is used for dividing the accommodating space into a
stock solution area and a filtrate area, a U-shaped
pipe of which the bent
pipe part is arranged downwards, wherein one end of the U-shaped
pipe is communicated to the filtrate area, and the other end of the U-shaped pipe is connected with a sample adding pipe; a
liquid storage bag which is arranged between the two straight pipe sections of the U-shaped pipe, wherein an inlet is formed in one side, close to the sample suction pipe, of the
liquid storage bag; a pluggingpiece which is used for plugging the open end of the sample suction pipe or the sample adding pipe, wherein a negative pressure unit is arranged on the
liquid storage bag and used for generating negative pressure to enable a
whole blood sample to enter the U-shaped pipe after being filtered by a filter membrane at the top of the sample suction tube, and the
whole blood sample is discharged from the sample adding tube after the negative pressure unit applies pressure. The quantitative sample
injector for
blood separation not only can filter red blood cells, but also can quantitatively inject samples.