Parameters for microscopic exam:
(1) number of items in a microscopic field
(2) area of the microscopic field in square mm
(3) thickness of the histologic section in microns = 10^(-3) mm
Parameters for smear:
(1) number of items counted
(2) volume of liquid sampled in microliterrs
volume for count performed on a histologic section in cubic mm (microliters) =
= (area of count in square mm) * ((thickness in microns) * 0.001)
density of item per microliter =
= (number of items counted) / (volume of material examined in microliters)
Limitations -There are several sources of error:
(1) variation in thickness of section or volume
(2) accuracy of count
