Centrifugal Cytology Technology

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Publications in Reverse Chronological Order.


Centrifugal Cytology patent that can be downloaded.

Swinging Buckets, R. C. Leif , 4,250,830 (1981).


Disclosed is a centrifugal cytology swinging bucket for providing multiple dispersions of fixed cells or other particles onto a microscope slide or similar substrate, the bucket comprising a slide holder for receiving a slide and a transparent sample block having a sample chamber with drill holes for fluid communication between fixative cups, such fixative cups having porous frits therein. The bucket further comprises a pair of holddowns each having an eccentric cam and a lever protruding therefrom.

CellFuge published patent application that can be downloaded.

Centrifugal Cytology System, Chamber Block and Method for the preparation of Treated Monolayers of Sample Material, R.C. Leif, published WO 03/104801 (2003).


An apparatus and method for the automated preparation of treated monolayers of sample material, comprising: a centrifuge having a rotor carrying removable chamber blocks; sample and treating agent dispensers and control system. First centrifugal force sediments a monolayer of sample material discreetly onto a receiving surface member on one of the chamber blocks, while the same centrifugal force opens a valve in the chamber block to drain sample material. Then, centrifugal force delivers sequentially into discrete chamber blocks discrete treating agents, during which time the sample material monolayer is held in place on the receiving surface member by centrifugal force. Then each chamber block is drained centrifugally through its already opened valve. Each treated sample material is confined to an individual chamber block. Batch and random access delivery of treating agents can be employed. Each chamber block includes separate inlets for the sample and treating fluids.


Centrifugal Cytology methods paper that can be downloaded.

Methods for Preparing Sorted Cells as Monolayer Specimens

No Abstract

Centrifugal Cytology paper that can be downloaded from Wiley-Liss.

S. Bajaj, J. B. Welsh, R. C. Leif, J. H. Price, Performance of a Custom Scanning Cytometer on a Model Preparation of Fetal nRBCs, Cytometry Vol. 39 (4), Pages 285 - 294 (2000).



The performance of a fully automated scanning cytometer incorporating previously reported high-precision autofocus and accurate image segmentation was evaluated for the detection of ultra-rare cells using a model of fetal nucleated red blood cells (fnRBCs) in the maternal circulation. These distinctive scanning cytometry techniques were expected to markedly improve sensitivity and specificity.


Normal adult blood and fetal red blood cells were stained with fluorescein isothiocyanate-conjugated anti-fetal hemoglobin and 4,6-diamidino-2-phenylindole, a nuclear dye. Adult cells were spiked with fetal cells to create ratios of about 1 fnRBC in 107 nucleated cells and deposited in monolayers on slides using centrifugal cytology. Rare-event performance parameters were reviewed, formalized, and applied to test the new instrument using this cell model.


Fifteen slides were analyzed to establish performance by comparison with manual detection, and four sets of four slides each were then scanned to explore the limit of detection. Results were an average sensitivity of 91%, an average specificity error of 12.3 false-positives per million cells, and repeatability of 100% at a cell analysis rate of 862 Hz. With addition of a quick interactive step subsequent to scanning, the false-positive rate dropped to a total of only one artifact over the 15 experiments. The instrument succeeded at locating 1 fnRBC in 20 million adult cells, the lowest limit of detection tested.


This consistently high performance, coupled with the capability of scanning arbitrarily large numbers of cells, validates the considerable potential of precise high-speed autofocus and accurate real-time image segmentation for ultra-rare event detection. Cytometry 39:285-294, 2000 © 2000 Wiley-Liss, Inc.

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