A WBC differential count gives us information regarding the proportion and numbers of individual leukocytes in the patient’s sample, including significant morphological changes. This can provide useful diagnostic information in cases of inflammation, infection, and antigenic responses. METHOD Equipment Stained PBS, microscope with 100×objective lens and cell counter. Procedure It is important that examinationand counts be performed withinthe monolayer area of your slide Scan the slide in a methodical grid pattern, in order not to cover the same area twice. Counts can be completed quickly under 400×magnification, but if you are also evaluating morphology, 1000×magnification should be used. Count a minimum of 100 WBCs. (If the total WBC Count is increased, 200 cells should be counted to maintain accuracy.) Calculations Relative count: No. of Cell Type Seen = ___% 100 Absolute count: Relative (%) x WBC Count (10³/ L) = ___ x 10³/μL 100 Note: Check your math: • Relative counts of each cell type should add up to equal 100 • Absolute counts of each cell type should add up to equal your WBC count.