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Home > Wellness Resources > Health Library > Thick and Thin Blood Smears for Malaria
Doctors use thick and thin blood smears to determine whether you
have malaria. If one test is negative and no parasites are found, you will have
repeated blood smears every 8 hours for a couple of days to confirm that there
is no malaria infection.
Blood smears are taken most often from a finger prick. Thick and
thin blood smears will let doctors know the percentage of red blood cells that
are infected (parasite density) and what type of parasites are present.
To date, microscopic examination of thick and thin blood smears is
the easiest and most reliable test for malaria.
Results of thick and thin blood smears may show:
No parasites are present in red blood cells. Your doctor will
repeat the test every 8 hours for 1 or 2 days if he or she still suspects that
you have malaria.
Parasites are present in red blood cells. The infecting species
of Plasmodium is identified. Also, the percentage of red
blood cells infected by the Plasmodium parasite
(density) is determined.
Treatment may vary depending on the:
Blood smears are the most reliable tests for malaria. You may want
to ask whether a thick or thin blood smear, or both, is planned. A thin blood
smear will identify the species of the malaria parasite. This information is
important to prevent or anticipate life-threatening complications if
P. falciparum is the source of infection.
Complete the medical test information form (PDF)medical test information form (PDF)(What is a PDF document?) to help you prepare for this test.
April 11, 2013
E. Gregory Thompson, MD - Internal Medicine & W. David Colby IV, MSc, MD, FRCPC - Infectious Disease
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