The CSF Diluting Fluid is used for RBC & WBC counting in Cerebrospinal Fluid analysis.Cerebrospinal fluid is the product of continuous secretory activity of the choroid plexuses of the brain ventricles.The cells in CSF rapidly deteriorate or get lysed and become enmeshed in fibrin or form clump. Hence, the cell count is determined immediately. The diluting fluid removes the red blood cells and stains the leucocytes.