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(2) Place the edge of another slide (spreader) on the specimen slide at a 30° angle.
(3) Slide the spreader slide toward the drop of blood until contact is made.
(4) Immediately push the spreader slide toward the opposite end of the specimen slide, drawing the
blood behind it. The smear should cover 1/2 to 2/3 of the slide.
b. Prepare the thick smear.
(1) Place 3 or 4 drops of the blood specimen at the end of a slide.
(2) Use a corner of another slide to stir the drop over an area about the size of a dime. It is
approximately the proper thickness if ordinary newsprint is just legible when looking through the
freshly prepared smear. At least two thick and two thin smears should be prepared for each
specimen.
NOTE: A positive control slide should be stained with all malaria specimens when available.
c. Allow the smear to air-dry in a flat position.
- Write the name or identification number of the patient in the thick area of the thin smear with a
lead pencil. - Stain the smear within 24 hours after air-drying and examine for uniform staining qualities.
a. Fix the thin smear in methanol for 3 to 5 seconds.
CAUTION: Do not allow the thick smear to come in contact with the methanol or near the methanol
vapors because this will fix the cells.
b. Allow the smear to air-dry.
c. Dip the thick smear in distilled water 3 to 5 times so that the stain will be adequately absorbed,
and to lyse intact RBCs.
d. Allow the smear to air-dry.
e. Place the entire slide in staining solution for 10 minutes.
f. Dip the entire slide in distilled water for 20 seconds or more (for desired color balance).
NOTE: Time will depend on the age, thickness, and density of the smear.
g. Remove the slides from the water and allow them to air-dry, standing on end on absorbent paper.
CAUTION: Do not blot the slides dry. This will damage the blood smears. - Examine the entire smear under the oil immersion objective.
a. If malarial parasites are present in the thick smear, report “Plasmodium species seen”. Confirm by
reading the thin smear and report by genus and species.
b. If no malarial parasites are present, report “No Plasmodium species seen.”
c. If other blood parasites are present, report by genus and species. - Record the results in the logbook and on the laboratory request form.
Lab Procedure: Tzanck Stain
COL Warren Whitlock, MC, USAWhen: To diagnose herpes lesions from herpes simplex or herpes zoster.
What You Need: Giemsa stain, Pap stain, Wright’s stain, slides/coverslip, microscope, #15 blade
What To Do:
- Obtain specimen. Gently rupture fresh vesicle with #15 scalpel blade. Gently scrape mushy debris from
vesicle base using curved belly of blade. Do NOT use cotton swab. Smear debris onto microscope slide.
Sample 3-4 vesicles if possible. - Prepare specimen. Gently heat slide over match. Air dry (fix in methyl alcohol if Giemsa is used). Place
drops of stain (Wright’s stain). Allow stain to sit on slide for over 1 minute. Rinse off stain under gently
running water. Put on a drop of immersion oil or mineral oil. Apply cover slip - Examine specimen. Examine under 10x power. Scan for smear bands. Background of lightly stained
debris. Look for darkly stained cells. Examine cells under 43x power. Positive test: multinucleated giant
cells: Herpes Simplex Virus (HSV), Varicella Zoster Virus (VZV)