There are several diluents that may be used for CSF counts. Normal saline should be used to make dilutions for total cell counts. Diluting fluids for WBC counts include:
- crystal violet/acetic acid
- gentian violet/acetic acid
- toluidine blue 0 and saponin
These fluids stain the white cells and lyse the red cells. The red cell count can be obtained by subtracting the white cell count from the total count.
Low power (10x) may be used for the total count while the high power objective (40x) is suggested for the white cell count, especially if the white cells are to be differentiated into segs, lymphs and monocytes.