Blood samples were drawn in 5 mL tubes with
anticoagulant. Each tube was then mixed well and divided
into three subgroups. In group 1, a conventional thin blood
smear was made. In group 2, ~40 毺L of blood from the
original 5 mL tube was loaded into a plastic heparinized
hematocrit tube. One end of the tube was then sealed with
Critoseal® capillary tube sealant. Blood within this tube was
then centrifuged at high speed in a micro centrifuge for 2
minutes. Following centrifugation, the plastic hematocrit
tube was cut (~2 mm) below the red blood cell (RBC)/serum
interface. A thin smear was then made using the RBCs
collected from near the buffy coat. In group 3, blood was
collected in the capillary tube as described above for group
2. However, rather than centrifuging the blood sample,
the blood filled hematocrit tube was placed on end and
allowed to undergo passive gravitational sedimentation for
4 hours. Following this sedimentation, the tube was cut and
a blood smear made as described above. Following smear
preparation, all samples were stained with Giemsa stain. The
presence of malaria-infected red blood cells was determined
and enumerated by resident hospital or clinic technicians.