The stability of the CSF sample varies depending on the procedures ordered. Hematologic analysis of CSF samples should be performed within one hour of fluid aspiration. Both red blood cells (RBCs) and white blood cells (WBCs) have limited stability in CSF because CSF is hypotonic and cells can rapidly lyse. Timing is especially critical for WBCs since both the number and type of cells present are clinically important in diagnosing cases of meningitis as well as detecting CNS leukemic involvement.
CSF samples for hematologic testing should be maintained at room temperature prior to testing. Refrigeration is also not recommended for culture specimens since fastidious organisms such as Haemophilus influenzae and Neisseria meningitidis may not survive at refrigerated temperatures.
