Lab Test

Differential Cell Count (Cerebrospinal Fluid and Other Body Fluids)

CSF Cell Differential

Test Codes

CSF: Antrim #20738, Body Fluids: Antrim #20745




This test is not orderable. It is a reflex test for CSF or Body Fluid Cell Count. Please see Cell Counts (Cerebrospinal Fluid and Other Body Fluids) for collection, transport, and storage information. 


Sunday – Saturday, 24 hours a day. STAT results available within 60 minutes if no further verification is necessary. Routine results are available within 3 hours. 

Reference Range

Pleural Fluid: PMN: 0-25% Mononuclear: 0-75%.
Synovial Fluid: PMN: 0-25% Mononuclear: 0-75%. 

Test Methodology

Cytospin Preparation.


All CSF specimens and Pediatric Hematology fluids with WBC counts within the normal range (less than or equal to 5 WBC/mcL) will have a CSF or fluid scan differential performed. RBCs, PMNs and mononuclear cells will be reported if present. All specimens with WBC counts greater than or equal to 6 WBC/mcL will have a differential performed. 

Cerebrospinal fluid may be examined as an aid in the diagnosis of meningitis, subarachnoid hemorrhage, encephalitis, CNS syphilis, CNS leukemia, CNS tumor and multiple sclerosis. In general, CSF changes due to a viral etiology will exhibit increased lymphocytes and those changes due to a bacterial etiology will show increased neutrophils. Other body fluids may be examined to determine the etiology of effusions and can sometimes be of extreme usefulness in distinguishing an inflammatory from malignant etiology.

Farmington Hills: Differentials are performed on all body fluid specimens with WBC counts greater than 5. CSF scans are not performed. 

Clinical Utility

Normal body fluids are clear, colorless and hypocellular. A change in physical appearance, an increase in cell count and differentiation of WBC may indicate a variety of diseases. 

CPT Codes



Last Updated


Microtainer® and Vacutainer® are registered trademarks of Becton, Dickinson and Company.
UroVysion® is a registered trademark of Abbott Laboratories. ThinPrep® is a registered trademark of Hologic, Incorporated.