Stabilization media increases recovery in paucicellular cerebrospinal fluid specimens submitted for flow cytometry testing.

BACKGROUND: Flow cytometric immunophenotpying (FCI) of cerebrospinal fluid (CSF) and other paucicellular fluids has been demonstrated to have increased sensitivity in detection of lymphoma and leukemia when compared to cytomorphology [(1) de Graaf et al., Cytometry Part B 2011, 80B:271-281; (2) Szamosi et al., CLSI Document H56-A-Body Fluid Analysis for Cellular Composition; Approved Guideline, Wayne, PA: Clinical and Laboratory Standards Institute, 2006; (3) Kraan et al., Flow Cytometric Immunophenotyping of Cerebrospinal Fluid. Current Protocols in Cytometry, Hoboken, NJ: Wiley, 2008]. However, low cellularity has been an historical problem with these samples. Several studies indicate that immediate addition of a stabilization media (e.g., RPMI with fetal calf serum (FCS)) to CSF improves the cell yield for FCI [(1) de Graaf et al.]. Such stabilization medias can, however, significantly increase cost.
METHODS: We compared FCI results in CSF stabilized with RPMI 1640 (without additional additives) to results obtained using non-stabilized CSF. Samples were processed according to published CLSI guidelines [(2) Szamosi et al.].
RESULTS: About 98/105 (93%) CSF specimens stabilized with RPMI had adequate numbers of viable cells (>100) for performing FCI. About 65/217 (30%) CSF specimens without stabilization had adequate numbers of viable cells for analysis (70% either quantity not sufficient (QNS) or specimen viability below analytical limits).
CONCLUSIONS: Utilizing RMPI without FCS as a stabilization media results in increased cell yield and improved FCI results. We have found FCS is not required to achieve high quality results in FCI of paucicellular CSF specimens.