Sedimentation cytology in central nervous system leukaemia with a new simple apparatus.

The clinical usefulness of a newly devised, simple apparatus, the Nishimura fluid sedimentation chamber, is described. The latter consists of an open-ended plastic tube, an absorbent paper with a central hole, and a glass slide which are stuck to each other with double-sided plastic adhesive tape with a central hole of equal size. The chamber is set to allow 0.5 ml of cerebrospinal fluid (CSF) to be absorbed in 15--20 min. The principle of the sedimentation relies on the absorption of the fluid portion into the absorbent paper with the cellular elements sedimented onto the glass slide. Thin stationery paper is used as the absorbent material which controls sedimentation speed and minimizes cellular loss. 190 CSF specimens obtained from 28 patients with acute leukaemia were processed by this method. The results obtained showed that sedimentation using this simple chamber is quite reliable for the recognition of small number of abnormal cells in the CSF producing little or no noticeable cellular damage. This technique may be applied to other clinical situations in which fluid cytology is useful in establishing a diagnosis or in evaluating clinical progress.