Laboratory diagnosis of malaria
Plasmodium malariae
Basic guidelines
A. Capillary blood should be obtained by fingerstick, or venous blood should be obtained by
venipuncture.
B. Blood smears, at least two thick and two thin, should be prepared as soon as possible after
collection. Delay in preparation of the smears can result in changes in parasite morphol-
ogy and staining characteristics.
C. Schüffner’s dots can be demonstrated in Giemsa stain, which is preferred to Wright or Wright-
Giemsa stains.
In P. malariae infections, red blood cells (rbcs) are normal or smaller than normal (3/4×) in size.
1. Rings
P. malariae rings have sturdy cytoplasm and a large chromatin dot.
Ring in a thick blood smear. Rings in thin blood smears.
2. Trophozoites
P. malariae trophozoites have compact cytoplasm and a large chromatin dot. Occasional band forms
and/or “basket” forms with coarse, dark-brown pigment can be seen.
Trophozoite in a thick blood smear. Band-form trophozoites in thin blood smears.
