When a spinal tap is performed correctly, the cell types found in the cytospin present a "snapshot" of the CSF cell content. When there is difficulty obtaining a clean tap, the cell types present will reflect the type of fluids that are co-mingled with the CSF. In traumatic taps, the cell types and proportions of red and white blood cells present will mirror that found in the patient's peripheral blood, as there has been a contamination of peripheral blood (from the trauma) mixed into the CSF during the sample collection.
