Automated cerebrospinal fluid cytology: limitations and reasonable applications

To evaluate the precision and clinical applicability of the Bayer ADVIA 120 cytometer (Bayer Healthcare, Fernwald, Germany) for cerebrospinal fluid (CSF) cell count and differentiation.

One hundred six analyses of CSF from 98 patients by the ADVIA 120 were compared with routine cell count and microscopic differentiation. Correlation coefficients were calculated.

In general, the total cell counts of both methods correlated well. The best correlations were seen at higher cell counts, > or = 100 cells per microliter with < 100 erythrocytes per microliter. The best correlations of cell differentiation were seen for lymphocytes and neutrophils, while the results for monocytes and eosinophils were less precise. In some cases, considerable differences between automated and microscopic cell counts and differentiation were seen that were relevant to clinical decision making. The detection of pathologic cell types, such as hemosiderophages, mitoses and neoplastic cells, was not provided by automated cytometry.

When experienced personnel are not available, a preliminary cell count and differentiation between neutrophilic and lymphocytic reactions by automated cytometry may be valuable in allowing initial therapeutic decision making. Since the detection of pathologic cell types is not provided and the precision at low cell counts is only moderate, a personal microscopic evaluation of each sample is still indispensable to avoid misdiagnoses.