Methods, such as using a fan to dry blood films faster, are especially important when:

a. The patient is very anemic or high humidity exists.
b. The patient has polycythemia or high humidity exists.
c. The sample is over 6 hours old.
d. No one is available to blow on the blood film.

ANS: A
When the blood film dries slowly on the slide, red cell and drying artifacts make it extremely difficult to evaluate red blood cell (RBC) morphology. Humidity adds to this problem, as does the high plasma volume found in an anemic patient. Drying the slide with a fan can be beneficial.