Preparation of thick and thin blood films and Giemsa staining

(parasite) (Anopheles mosquitoes)

Malaria is caused by a small living organism, called a (________)

which infects a person’s red blood cells. It is transmitted from one

person to another by the bite of female (____________).

thick film

is always used to search for malaria parasites.

dehaemoglobinization

The film consists of many layers of red and white blood cells. During

staining, the haemoglobin in the red cells dissolves

(_______________), so that large amounts of blood can be examined

quickly and easily.

thin film

is used to confirm the malaria parasite

species, consists of a single layer of red

and white blood cells spread over less than half the slide.

(clean slide) (small drop) (45)

METHOD IN PREPARING THIN BLOOD FILM

Using another (_______) as a spreader

and with the slide with the blood resting

on a flat, firm surface, touch the (______) of blood with the edge of the

spreader, allowing the blood to run right

along the edge. Firmly push the spreader

along the slide, keeping it at an angle of

(___). The edge of the spreader must

remain in even contact with the surface

of the other slide while the blood is

being spread.

(corner of the spreader) (1 cm)

METHOD IN PREPARING THICK BLOOD FILM

Handling the slides by the edges or

a corner, make the blood film by

using the (____________)

to join the drops of blood, and

spread them to make an even,

thick film.

The circular thick film should be

about (____) in diameter.

(Poorly positioned) (Greasy) (chipped)

COMMON FAULTS IN PREPARING BLOOD FILMS

•(___________) blood

films

•Too much blood

•Too little blood

• (_________) slides

•Edge of the spreader slide

(_______)

(Giemsa stain) (eosin) (methylene blue)

(_________) is an alcohol-based Romanowsky stain. Giemsa

stain is a mixture of (_____), which stains parasite chromatin and

stippling shades of red or pink, and (__________), which

stains parasite cytoplasm blue.

(10%) (3%)

GIEMSA STAINING

2 TYPES:

• Rapid (____) method

• Slow (____) method

(thick film should not be fixed.) ( 5-10 minutes)

GIEMSA STAINING

Rapid (10%) method

FIXATION PROCEDURE:

Once the thin film has dried, fix it by adding a few drops of methanol or

by dipping the film in a container of methanol for a few seconds. To

permit dehaemoglobinization, the (________________)

STAINING PROCEDURE:

Gently pour the stain onto the slide or use a pipette. Stain for (_________). Gently flush the stain off the slide by adding drops of clean

water. Place slides, film side downwards, in a slide rack to drain and dry.

(Exposure of the thick film to methanol or methanol vapour should be avoided) (7.2) (30-45 minutes)

GIEMSA STAINING

Slow (3%) method

FIXATION PROCEDURE:

Once the thin film has dried, fix it by adding a few drops of methanol, or by dipping it into a container

of methanol for a few seconds. Allow the thin film to dry thoroughly by evaporation. (___________________________________). If the methanol does fix the thick

film, dehaemoglobinization will not be possible.

STAINING PROCEDURE:

Place the slides in a staining trough. Prepare a 3% Giemsa solution in buffered distilled or deionized

water, pH (____), in sufficient quantity to fill the trough and cover the slides. Stain for (____________),

out of sunlight.

Pour clean water gently into the trough to float off the iridescent scum on the surface of the stain.

Rinse rapidly in clean water.