1. PREPARATION OF BLOOD
FILM FOR MALARIA
PARASITES
MALARIA DIAGNOSIS WORKSHOP
29 JUNE – 2 JULY 2010

2. Two types of blood film for malaria parasites
Thick Blood Smear – use to determine if parasite is
present.
Thin Blood Smear – use to confirm the Plasmodium
species present

3. Before making blood film…
 Wear gloves prior to taking blood samples or handling
blood.
 Avoid getting blood, including dry blood from films, on
your fingers or hands.
 Cover cuts on your hands with waterproof dressing.
 Avoid accidentally pricking yourself when handling sharp
instruments
 Wash your hands with soap and water after you finish a
job.
 If you get blood on your skin, quickly wipe it off with a
cotton swab dampened with alcohol; then, wash the
affected area with soap and water as soon as
 possible.

4. Materials for Preparation of Malaria
Smears
 Clean and wrapped slides
 Sterile lancets
 70% ethanol and water
 Absorbent cotton wool
 Surgical gloves
 Lint-free cotton cloth
 Slide box or cover to exclude flies and dust
 Record form or register
 Soft lead pencil; ball-point pen

5. PROCEDURES:
1. RECORD PATIENT DETAILS ON A REGISTER

6.  Get ready clean
microscopic slide
 glass slides of
superior’ quality, with
frosted end.
 The frosted end
should be used to
label the slide.

7. PREPARATION OF BLOOD FILM FROM
FINGERPRICK
2. Wear glove and hold
the patient’s left hand
with palm facing upwards.
Select third finger from
the thumb
The thumb should never
be used for adults or
children.
Note : Good films may be prepared
directly from fingerprick blood,

8.  Clean the finger with
a piece of cotton wool
lightly soaked in 70%
ethanol.
 Dry the finger with a
clean cotton cloth,
using firm strokes to
stimulate blood
circulation.

9.  For infant – use the
toe

10. 4. Use sterile lancet to
prick the finger

11. 5. Apply gentle pressure
to the finger to allow
the blood to ooze out
6. Wipe off the first drop
7. Apply further gentle
pressure for more
blood

12. 8. Place blood on clean
glass slide to make
thick and thin blood
film on a slide

13.  Place the spreader
slide in contact with
the drop of blood at
an angle..
 Let blood spread
along the edge of the
spreader slide.

 gently push towards
the other end of the
slide

14. Angle too flat
> film too long
Angle too steep
Thin Blood Film > film too short

15. Thin Film
 Good preparation - feathered end of
the film should be centrally located
on the slide with free margins on
both sides,
when properly prepared, it will be
only one cell layer thick at this end.
 Badly prepared smears can cause
presence of streaks - as a result of
chipped spreader
 holes in the film indicate faulty
preparation and dirty or greasy
slides, respectively.

16. TOO MUCH BLOOD
OK
Combination of thick and thin blood on the same slide

17. Thick blood film – spread the drop of blood
using a corner of the spreader.
Spread the drop in one circular direction to
make even thick film, size of a 1 cm
diameter. Do not stir the blood.

18. Preparation of thick blood film using …….
Plastic pipette

19.  Using wooden stick

20. Good thick blood film
• The right thickness,
• You should be able to
read the newspaper,

21. Avoid doing these
It should be round Thick film too thick

22. Labeling
 With frosted end
 use a pencil
 Without frosted end
use diamond pencil
 Do not label on the
blood film
 Do not use a ball pen
 Do not use a paper
label

23. Drying slides
 Incubator 37oC  Hair dryer?
 Leave standing on a  A fan?
rack on lab bench
 In a slide tray with the
cover open
Do not leave on the bench in a laboratory
unattended because it will be eaten by insects.
Slides must be dried completely before they
are packed for storage or transport.

24.  Venous blood can be
 used instead of from
finger prick
 Use vacutainers with
 anticoagulant (EDTA)

25.  For preparing thin and
thick films use a glass
capillary to drop the
ETDA-blood.
 plastic pipette ? Yes
provided no air bubles

26. The use of anticoagulated (EDTA) blood may
cause the following :
 smears require longer time to dry
 thick smears tend to flake from the slide
 stain quality is affected,
 stippling of infected RBC’s may not be visible
 parasite forms may be distorted and may lyse
 RBC’s may become crenated and look
fimbrinated

27.  Prepare smears as soon as possible after
collecting venous blood (less than 2
hours after collection) to avoid:
Changes in parasite morphology
Changes in the RBC morphology
(these effects can compromise
correct identification of species)
Staining characteristics

28. Thank
You
For your attention