Experiments in the preparation of blood smears

Summary

Learn and master the methods of smearing and staining human blood.

Operation method

Experiments in the preparation of blood smears

Materials and Instruments

Blood
Sterilized alcohol Ritter's stain Distilled water
Slides Coverslips Skimmed absorbent cotton Blood piercing needles Oil for oil microscope Microscope

Move

I. Preparation of blood smears

Follow each of the steps below.

(i) Blood collection

Rub the area to be collected, such as the earlobe or fingertip, before blood collection to get the blood flow going. Sterilize the skin with alcohol and leave it to dry. Hold the area with the thumb and index finger of the left hand, and then prick it with a sterilized hypodermic needle, and the blood will flow out naturally. If the blood does not flow well, gently squeeze and wipe off the first drop of blood with sterilized cotton.

(ii) Smear

Dab a little of the second drop of blood on the right end of a clean slide and use the other slide as a slide. Place the end of this slide obliquely on the left edge of the blood drop on the first slide at an angle of 30o~40o degrees. Push the slide back slightly so that it is in contact with the blood droplet figure, so that the blood is stretched out to either side of the end of the slide and fills in the oblique angle between the two slides. At this point the push piece is pushed forward and the blood follows the push piece, i.e., it is coated into a blood film (Figs. 2 and 3).

When pushing the slice, a certain speed and angle between the two slices should be maintained, and the slice should be pushed forward continuously without interruption. The thickness of the blood film can be adjusted by the size of the blood droplet, the speed of pushing the film and the size of the angle between the two films. If the blood droplet is small, the propulsion speed is slow, and the angle between the two tablets is small, the smear will be thin; on the contrary, it will be thick. Thick smears are suitable for leukocyte sorting, and leukocytes are easily found.

(iii) Staining

After the blood film is dry, several drops of Ritter's dye (formula: 0.1 g of Ritter's dye dissolved in 60 ml of methanol) are placed on the blood film, so that the blood film is completely covered by the dye. After about 1 min, add 1.5 times the amount of buffer or distilled water. Immediately after the addition, the blood film was gently swabbed with the mouth.

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