[Elizabeth_Zeibig]_Clinical_Parasitology__A_Practi(z-lib.org)

CHAPTER 12 Artifacts and Confusers
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FIGURE 12-16 Stain precipitate.
FIGURE 12-13 Starch cells.
Unlike a malarial parasite, which typically
appears as a blue cytoplasm with a red chromatin,
clumped or fused platelets appear in various
shades of purple. In addition, malarial parasites
possess a more definite outline than clumped or
fused platelets.
FIGURE 12-14 Clumped/fused platelets.
Quick Quiz! 12-6
B
A
The major feature that distinguishes starch cells
from protozoan cysts is which of the following?
(Objective 12-1)
A. Presence of bacteria in the cytoplasm
B. Unusually large size
C. Shape
D. Lack of defined internal structures
FIGURE 12-15 Giemsa stain, 1000×. Platelet artifacts.
(A) intracellular (inside a red blood cell) and (B) outside a
red blood cell (extracellular). (Courtesy of WARD’S Natural
Science Establishment, Inc.)
that no karyosome or peripheral chromatin is
present. In addition, starch cells may be differentiated
from parasites because of their dark blueblack
appearance when stained with iodine.
CLUMPED OR FUSED PLATELETS
Clumped or fused platelets often appear on
Giemsa-stained blood film smears and may be
mistaken for malarial parasites, especially the
young trophozoite form (Figs. 12-14 and 12-15).
STAIN PRECIPITATE
Giemsa-stain precipitate may be visible on blood
smears and may be mistaken for malarial parasites
(Fig. 12-16 and 12-17). Stain precipitate is
usually bluer in color than malarial parasites and
varies in size and shape.
RED CELL ABNORMALITIES
Red blood cell abnormalities, such as Howell-
Jolly bodies or Cabot’s rings, may be present
on Giemsa-stained blood smears. These abnormalities
may be easily distinguished from
malarial parasites by their different staining
characteristics.