Is a differential cell count needed in CSF samples with normal cell counts?
A. Cerebrospinal fluid, or CSF, is submitted to the laboratory most often to evaluate for infection, hemorrhage, or malignancy. A cell count and differential count are routinely requested as part of this evaluation. It is logical to perform a differential cell count on a CSF sample with an increased number of cells. However, the issue has been raised of whether a differential count is needed in CSF samples with normal cell counts. Literature addressing this question is scant, but the following are guidelines on how members of the CAP Hematology/Clinical Microscopy Resource Committee handle the differential cell count on CSF samples. A Wright-Giemsa-stained cytocentrifuged slide is prepared for all CSF samples, regardless of the total cell count. In cases with a normal CSF cell count, the slide is used differently depending on the patient population. Cytocentrifuged slides from adults are always scanned for organisms or abnormal cells, particularly in patients with a history of maligna
