Optics: measuring and testing – Sample – specimen – or standard holder or support – Fluid containers
Reexamination Certificate
1997-05-07
2001-02-06
Pham, Hoa Q. (Department: 2877)
Optics: measuring and testing
Sample, specimen, or standard holder or support
Fluid containers
C356S335000, C377S010000
Reexamination Certificate
active
06184978
ABSTRACT:
TECHNICAL FIELD
The present invention relates to fluid samples in flow cells and distributed on slides and, in particular, to a method for verifying that a fluid sample is flowing uniformly through the flow cell and is uniformly distributed on the slide.
BACKGROUND
A conventional flow cell and particle analyzer is shown, in plan view, in
FIG. 1
, and a particle analyzer is shown in block schematic form in FIG.
2
. The flow cell and particle analyzer automate the job of counting fluid particles suspended in a biological sample (for example, blood cells suspended in a serum sample or particles suspended in a urine sample). More generally, the flow cell and particle analyzer may be used to automate the job of counting any “particles of interest” that are suspended in a fluid sample.
Referring now to
FIG. 1
, the flow cell includes a body
10
containing a flow chamber having an inlet
12
through which the fluid sample is provided. The flow chamber also has an outlet
14
. A passageway
16
extends between the inlet
12
and the outlet
14
such that the fluid sample provided at the inlet
12
flows past an examination area
18
(shown by a dashed line in
FIG. 1
) and is discharged out of the passageway
16
via the outlet
14
.
During a sampling run, the fluid sample is surrounded on both sides by sheath fluid (e.g., saline solution) introduced into the passageway
16
from inlets
13
a
and
13
b.
A strobe light
32
(
FIG. 2
) illuminates the examination area
180
from below and a microscope
30
is focused on the examination area
18
from above. A CCD camera
34
receives the output of the microscope
30
to form a series of still frame images.
In particular, a frame grabber
40
“grabs” the still frame images and stores them in a memory. A CPU
56
combines selected components of the still frame images to generate composite images which represent the particles in multiple images. Thus, individual particles (for example, different types of blood cells) can be analyzed and sorted.
In order for the particle analyzer to perform reliably, the fluid sample having the suspended particles of interest must flow uniformly through the flow cell examination area
18
, without interruption. Even if interruptions occur relatively infrequently, when they do occur they will cause the determined particle counts to be inaccurate.
SUMMARY
In accordance with one embodiment of the invention, a particle analyzer verifies the uniformity of fluid flow through a flow cell examination area without reference to particles of interest (that may or may not be suspended therein). First, the particle analyzer inspects still frame images generated by a frame grabber of the flow cell and the light level in the examination area is determined. Then, a heavy stain is injected into the flow cell. Thereafter, the particle analyzer inspects further still frame images generated by the frame grabber of the flow cell and determines from the further images whether there is a uniformly decreased intensity in light level in the examination area (corresponding to the heavy stain flowing through the examination area). If so, then the flow of fluid through the flow cell examination area is indicated as being uniform. Otherwise, the flow of fluid through the flow cell examination area is indicated as being non-uniform.
In accordance with another embodiment of the invention, a particle analyzer executes statistical tests on counts of particles of interest in the fluid sample under analysis and uses these counts to determine whether the fluid sample is flowing uniformly past an examination area of the fluid particle analyzer. In particular, statistical parameters of the particle counts are calculated. Then, it is determined whether the calculated statistical parameters are within an allowable range for the parameters. Based on this determination, an indication is provided of whether the fluid sample is flowing uniformly past the examination area.
A better understanding of the features and advantages of the invention will be obtained by reference to the following detailed description and accompanying drawings which set forth an illustrative embodiment in which the principles of the invention are utilized.
REFERENCES:
patent: 4338024 (1982-07-01), Bolz et al.
patent: 4393466 (1983-07-01), Deindoerfer et al.
patent: 4519087 (1985-05-01), Deindoerfer
patent: 4612614 (1986-09-01), Deindoerfer et al.
patent: 4653078 (1987-03-01), Aritomi et al.
patent: 4696183 (1987-09-01), Mitsumaki et al.
patent: 4804267 (1989-02-01), Greenfield
patent: 5625709 (1997-04-01), Kasdan
Harvey Lee Kasdan, “Nonparametric Pattern Recognition”, A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in Engineering, University of Los Angeles, 1971, pp. 74-77, 201, 214-221.
Kasdan Harvey
Ko Jaehyl
International Remote Imaging Systems, Inc.
Limbach & Limbach LLP
Pham Hoa Q.
Yin Ronald L.
LandOfFree
Method and apparatus for verifying uniform flow of a fluid... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for verifying uniform flow of a fluid..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for verifying uniform flow of a fluid... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2558324