Blood Film for MalariaThick and Thin Blood Film

Hawler Medical University – College of Medicine

Prepared by:

Ibrahim Hussein

Ahmad Mazn

Aram Majeed

Objectives

The purpose of thick and thin blood film Procedures of thick and thin blood film Stains used for thick and thin blood film Microscopic features of thick and thin blood

film Advantages and disadvantages of thick and

thin blood film

Blood film

When a peripheral blood sample is smeared on a slide and stained, it is known as a peripheral blood film (peripheral blood smear).

The most commonly used technique for blood examination

There are two types pf blood film which are:

1- Thick blood film

2- Thin blood film

The Purpose of Blood film

It allows for examination of the physical characteristics of the red cells, white cells and platelets under the microscope.

It helps detect parasites or abnormal cells in the blood.

Examination of blood films is important in the investigation and management of infections, wide range of illnesses, including detection of blood-borne parasites, like malaria.

The Purpose of thick and thin blood films A thick blood film is a drop of blood on a

glass slide. Thick blood smears are most useful for detecting the presence of parasites because they examine a larger sample of blood. (Often there are few parasites in the blood at the time the test is done.)

A thin drop of blood that is spread across a large area of the slide. Thin blood smears helps doctors discover what species of malaria is causing the infection.

Procedure of preparing a blood film

Three basic steps to make blood film:

1- Preparation of blood film.

2- Fixation of blood film.

3- Staining of blood film.

Preparation of blood film

1- Get ready clean microscopic slide.

2- Blood is obtained from the tip of a finger or a heel or big toe (in infants). The skin should be carefully cleaned with ether or ethanol, and allowed to dry. Use a sterile lancet prick the finger, wipe off the first drop then squeeze gently to obtain a good drop of blood.

3- Place blood on clean glass slide to make thick and thin blood.

4- For a thick blood film:

Touch the drop on a glass slide.

Then spread the blood evently with the corner of another slide to make a square or a circular patch of moderate thickness (with a diameter of 1-2 cm), it should be possible to read through it.

Dry the slide, while protecting it from dust, flies and insects.

Preparation of blood film

5- For a thin blood film:

The drop of blood should be smaller than for the thick film.

Apply the edge of another glass slide to the top of the drop of blood at an angle of 45°, allowing the blood to spread along its edge, then push the spreader slide forward keeping it at the same angle.

A properly made thin film should consist of an unbroken layer of red blood cells with the tongue of the film not touching the edge of the slide. The thin film must be dried immediately by waving the slide from side to side or by holding it for a few seconds in front of a fan this ensures a good preservation of the shape of the cells.

Good blood films Poor blood films

LipemiaRoeleaux

Stains used for thick and thin blood film• Giemsa’s stain

• Leishman’s stain

• May-Grunwald stain

• Jenner’s stain

• Jenner-Giemsa

• These stains allow for the detection of WBCs,RBCs, and platelet abnormalities

Staining principles used for thick and thin blood film

Many differential stains have been developed for the detection of malaria parasites but the Romanowsky stains that stain the nucleus red and cytoplasm blue have proved the most adaptable and reliable for routine work.

Prior to staining, cells must be fixed to the glass slide with acetone-free methanol, either alone or in solution with dye. Addition of a buffer solution to the dye changes the pH of the solution and ionizes the reactants to initiate the pH- dependent staining process.

Staining principles used for thick and thin blood film

Acidic cellular elements such as nucleoproteins, nucleic acids and primitive cytoplasmic proteins, react with the basic dyes, methylene blue and its oxidative products. These elements are basophilic and stain variations of blue.

Basic cellular elements such as hemoglobin molecules and some cytoplasm of WBCs, have an affinity for the acidic dye, eosin. These elements are acidophilic and stain orange-red.

Microscopic features of thick and thin blood film

• Plasmodium are always intracellular, blue cytoplasm with red chromatin.

• We can see ring stage, schizont & merozoit inside RBCs.

• Plasmodium spp; all asexual stage are seen.

• Plasmodium falciparum; only ring stage and gametocytes are seen.

P.falciparum

Schizont

Gametocyte

Gametocyte

Schizonts

P.vivax

Advantages and disadvantages of blood film

Thick film: Advantage: more sensitive to detect the

parasite than thin film. Disadvantage: morphologic feature are

not seen, so the species are not identified.

Advantages and disadvantages of blood film

Thin film: Advantage: morphology is better seen, so

the species are identified.

Disadvantage: because less amount of blood is examined, so it is not sensitive for detecting the parasite.

Summary Blood film allows for examination of the physical

characteristics of the red cells, white cells and platelets under the microscope.

It is the most commonly used technique for blood examination.

Thick blood smears are most useful for detecting the presence of parasites while thin blood smears helps doctors discover what species of malaria is causing the infection.

Giemsa’s stain and Leishman’s stain are stains most commonly used for staining blood films

For malaria Romanowsky stains commonly used which stain the nucleus red and cytoplasm blue.