U.S. patent number 3,901,658 [Application Number 05/493,006] was granted by the patent office on 1975-08-26 for whole blood analysis rotor assembly having removable cellular sedimentation bowl.
This patent grant is currently assigned to The United States of America as represented by the United States Energy. Invention is credited to Carl A. Burtis, Wayne F. Johnson.
United States Patent |
3,901,658 |
Burtis , et al. |
August 26, 1975 |
Whole blood analysis rotor assembly having removable cellular
sedimentation bowl
Abstract
A rotor assembly for performing photometric analyses using whole
blood samples. Following static loading of a gross blood sample
within a centrally located, removable, cell sedimentation bowl, the
red blood cells in the gross sample are centrifugally separated
from the plasma, the plasma displaced from the sedimentation bowl,
and measured subvolumes of plasma distributed to respective sample
analysis cuvettes positioned in an annular array about the rotor
periphery. Means for adding reagents to the respective cuvettes are
also described.
Inventors: |
Burtis; Carl A. (Knoxville,
TN), Johnson; Wayne F. (Loudon, TN) |
Assignee: |
The United States of America as
represented by the United States Energy (Washington,
DC)
|
Family
ID: |
23958504 |
Appl.
No.: |
05/493,006 |
Filed: |
July 30, 1974 |
Current U.S.
Class: |
494/16; 356/39;
356/246; 422/72 |
Current CPC
Class: |
G01N
21/07 (20130101) |
Current International
Class: |
G01N
21/03 (20060101); G01N 21/07 (20060101); B04B
005/12 (); G01N 033/16 (); G01N 021/00 (); G01N
001/10 () |
Field of
Search: |
;23/253R,259
;356/39,197,246 ;233/26 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wolk; Morris O.
Assistant Examiner: Hagan; Timothy W.
Attorney, Agent or Firm: Carlson; Dean E. Zachry; David S.
Hamel; Stephen D.
Claims
What is claimed is:
1. A rotor assembly for a photometric solution analyzer of the
rotary cuvette type suitable for use in analyzing whole blood
samples comprising:
a. a generally disk-shaped main rotor body defining:
i. an annular plasma distribution manifold;
ii. a plurality of volume measuring chambers distributed in a
circular array, said volume measuring chambers being in liquid flow
communication with said plasma distribution manifold;
iii. means limiting the centripetal level of plasma in said volume
measuring chambers during operation of said rotor;
iv. a plurality of sample analysis cuvettes disposed in a circular
array about the periphery of said main rotor body, said sample
analysis cuvettes being in liquid communication with said volume
measuring chambers; and
v. means for loading reagents into said sample analysis cuvettes;
and
b. a sedimentation bowl nested within said main rotor body and
adapted to rotate with that body as a unit, said sedimentation bowl
comprising:
i. a hollow disk-shaped base portion, said base portion having a
centrally located top opening for receiving whole blood samples and
discharging displaced plasma; and
ii. an upstanding, open-ended, annular neck portion integrally
fixed to said base portion in register with said top opening, the
top end of said neck portion terminating within the center of said
annular plasma distribution chamber within a plane axially
intermediate to the axial extremities of such chamber.
2. The rotor assembly of claim 1 wherein said sedimentation bowl is
removably nested within said main rotor body.
3. The rotor assembly of claim 1 further including a plurality of
passageways communicating between said sample analysis cuvettes and
said volume measuring chambers, each of said passageways comprising
three radially extending interconnected passageway segments; a
first segment extending radially from a respective sample analysis
cuvette to a point centripetal to the centripetal ends of said
volume measuring chambers, a second segment extending from the
centripetal end of said first segment to a point centrifugal to
said volume measuring chambers, and a third segment extending from
the centrifugal end of said second segment to the centrifugal end
of a respective volume measuring chamber.
4. The rotor assembly of claim 1 wherein said volume measuring
chambers are axially displaced from said plasma distribution
manifold with the centripetal ends of said volume measuring
chambers radially overlapping the centrifugal extremity of said
plasma distribution manifold.
5. The rotor assembly of claim 4 wherein axially extending plasma
inlet ports communicate between said plasma distribution manifold
and respective volume measuring chambers, said inlet ports being
disposed on a common radius about the center of rotation of said
rotor assembly.
6. The rotor assembly of claim 5 wherein said means limiting the
centripetal level of plasma in said volume measuring chambers
comprises a plasma overflow chamber and a plasma overflow
passageway communicating between said plasma distribution manifold
and said plasma overflow chamber.
7. The rotor assembly of claim 6 wherein said overflow passageway
communicates with said plasma distribution manifold at a radius
centripetal to the common radius on which said plasma inlet ports
are disposed.
Description
BACKGROUND OF THE INVENTION
The invention described herein relates generally to photometers and
more particularly to an improved whole blood analysis rotor
assembly for a multi-station dynamic photometer of the rotary
cuvette type. It was made in the course of, or under, a contract
with the U.S. Atomic Energy Commission.
Fast photometric analyzers incorporating multi-station rotary
cuvette systems are becoming widely used in various laboratories
because of their ability to rapidly and accurately analyze large
numbers of samples. Of particular interest are blood tests
including glucose, LDH, SGOT, SGPT, BUN, total protein, alkaline,
phosphatase, bilirubin, calcium, chloride, sodium, potassium, and
magnesium. Since such tests are normally performed on blood plasma,
blood cells must be removed from whole blood samples prior to
analysis. Cuvette rotors designed to accept and automatically
process whole blood samples must, therefore, be capable of
separating plasma from cellular material. In addition, such rotors
must be designed for receiving a sample in a loading operation,
measuring discrete subvolumes of separated plasma from each sample
analysis cuvette and transferring the subvolumes into respective
cuvettes.
One rotor assembly which has been designed to accept and
automatically process whole blood samples is described in copending
application Ser. No. 489,305 of common assignee. That rotor is
difficult to clean since red cells are closely packed within
capillary sized passageways during a centrifugal separation
operation designed to separate the plasma and cellular components.
Also, because of its design which requires that part (about half)
of a sample be wasted, blood volumes are required greatly in excess
of that used in the actual analyses.
It is, accordingly, a general object of the invention to provide an
improved rotor for a multi-station photometric analyzer which is
suitable for use in performing whole blood analyses.
Another more particular object of the invention is to provide an
improved rotor for a multi-station photometric analyzer suitable
for receiving a whole blood sample, centrifuging the whole blood
sample to separate it into cellular and plasma components,
measuring discrete plasma subvolumes, and transferring the
subvolumes to respective sample analysis cuvettes.
Another particular object of the invention is to provide an
improved rotor for a multi-station photometric analyzer suitable
for receiving a whole blood sample wherein sedimented cellular
components are readily removable following sample analysis.
Still another object of the invention is to provide an improved
rotor for a multi-station photometric analyzer suitable for
receiving a whole blood sample wherein the volume of blood required
for analysis is minimized.
Other objects of the invention will be apparent from an examination
of the following written description of the invention and the
appended drawings.
SUMMARY OF THE INVENTION
In accordance with the invention, an improved rotor assembly is
provided for use in performing whole blood analyses in a
multi-station photometric analyzer. Included in the rotor assembly
is a generally disk-shaped main rotor body and a removable
sedimentation bowl nested within the main rotor body and adapted to
rotate with that body as a unit. Features defined by the main rotor
body include: an annular plasma distribution manifold for receiving
plasma displaced from the sedimentation bowl, volume measuring
chambers and passageways for receiving plasma from the distribution
manifold, means for receiving plasma overflow from the distribution
manifold, sample analysis cuvettes disposed in a circular array
about the rotor periphery and means for loading reagents into the
sample analysis cuvettes. The removable sedimentation bowl includes
a hollow disk-shaped base portion and an upstanding annular neck
portion through which whole blood samples are statically loaded
into the base portion and through which separated plasma is
displaced under dynamic operating conditions. Using the subject
improved rotor assembly, cellular components are removed from whole
blood samples and retained in the sedimentation bowl which can be
cleaned between operations or disposed of and replaced with a new
bowl.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawing, which is a top, cutaway, isometric
view of a rotor assembly made in accordance with the invention, the
rotor assembly is seen to include a sedimentation bowl 1 and a
disk-shaped main rotor body 2. The sedimentation bowl is shaped to
nest concentrically within the rotor body at the level of the rotor
body base and to rotate upon a turntable (not shown) with the rotor
body as a unit. As shown, the sedimentation bowl comprises a
shallow, hollow, disk-shaped base portion 3 and an upstanding
annular neck portion 4 through which whole blood samples may be
statically loaded into the base portion and separated plasma
displaced under dynamic operating conditions. Neck portion 4 is
provided with a slightly tapered inner surface having a larger
diameter at its end which is fixed to base portion 3 to ensure
movement of displacing liquid into the base portion during a plasma
displacing operation. The main rotor body in the preferred
embodiment is a vertically stacked, laminar construction comprising
a base 5, a divider plate 6, a chamber plate 7, and capping plate
8. The base plate 5 is an annulus of transparent material which
provides lower windows for the sample analysis cuvettes which is
sized to provide an opening for receiving sedimentation bowl 1.
Divider plate 6 is annular shaped and extends centripetally beyond
the inner periphery of the base 5, permitting upward projection of
the neck portion 4 therethrough. The divider plate 6 functions as a
vertical retainer for the sedimentation bowl and as a lower wall
for an annular plasma distribution manifold 9 formed in the
centripetal region between divider plate 6 and a tapered portion of
the chamber plate 7.
The chamber plate 7 is, in comparison with the outer laminations, a
thick annulus which provides a matrix defining the main functional
chambers and inner connecting passageways as described below. The
annular plasma distribution manifold 9 is formed by relieving a
shallow conical portion of the matrix from the lower centripetal
edge of the chamber plate. Plasma distribution manifold 9 extends
from axially below to axially above the upper extremity of neck
portion 4 when, as shown, sediment bowl 1 is fully inserted within
the main rotor body in operating position. A multiplicity (only one
shown) of plasma volumetric measuring chambers 10 are disposed in a
circular array and displaced axially above and radially overlapping
the distribution manifold 9. Plasma inlet ports 11 extend axially
and provide liquid communication between distribution manifold 9
and each measuring chamber 10 to permit passage of plasma from the
plasma distribution manifold to the respective measuring chambers.
Ports 11 are precisely located on a common radius to facilitate
equal filling of chambers 10 under centrifugal conditions. The
measuring chambers 10 are vented to manifold 9 by means of vent
ports 12 located centripetal to the plasma inlet ports 11.
A circular array of sample analysis cuvettes 13 is located
peripherally within the divider plate 6 and chamber plate 7. Sample
analysis cuvettes 13 are equal in number to, and are somewhat
angularly offset from respective plasma measuring chambers 10. One
reference cuvette, which is not in communication with a plasma
measuring chamber 10, may be provided for photometric blank
solutions. Corresponding measuring chambers 10 and sample analysis
cuvettes 13 are in communication through corresponding folded
passageways 14 which extend from the centrifugal extremity of each
measuring chamber 10 and the centripetal extremity of each sample
analysis cuvette 13. Each passageway 14 comprises three
interconnected, radially extended segments which describe an N
shaped path with a first segment 14a extending from the measuring
chamber radially outward to a point about equal to the radius at
which sample analysis cuvettes 13 are disposed, a second segment
14b extending radially inward from the centrifugal end of the first
segment to a point centripetal to the circle upon which commonly
lie the plasma inlet ports 11, and a third segment 14c extending
radially outward from the centripetal end of the second segment to
a sample analysis cuvette 13. At least one plasma overflow chamber
15 is defined within the matrix of the divider plate 6 in a
generally peripheral location. The overflow chamber 15 is in
communication with plasma distribution manifold 9 by means of an
overflow passageway 16 which enters the distribution manifold 9 at
a point just centripetal to the circle upon which lie plasma inlet
ports 11. Overflow passageway 16 extends from plasma distribution
manifold 9 upward to the top of the chamber plate 7, and then
centrifugally to enter the overflow chamber 15.
As shown, each sample analysis cuvette 13 is provided with a
cleanout passageway 17 extending from its lower centripetal
extremity to the cavity which is formed in base 5 upon removal of
sedimentation bowl 1 from its operating position. Plasma overflow
chamber 15 may likewise be provided with a cleanout passageway.
Capping plate 8 is superimposed on chamber plate 7 partially to
provide a top closure for the measuring chambers 10, sample
analysis cuvettes 13, passageways 14, plasma overflow chamber 15
and overflow passageways 16. The capping plate also provides a
matrix for forming reagent loading ports 18 (only 1 shown) which
permit direct loading access to each sample analysis cuvette from
the topside of the rotor assembly. Second cleanout passageways 19
extend between the reagent loading ports 18 and the centripetal
extremity 20 of annular capping plate 8 to provide for fluid
cleaning of the sample analysis cuvettes as do the first cleanout
passageways 17.
In operation, diverse test reagents are pipetted into the sample
analysis cuvettes 13 through the reagent loading ports 18 while the
rotor is kept stationary. Whole blood is statically loaded within
sedimentation bowl 1 and then centrifuged at about 4000 RPM to
sediment cellular components in the periphery of the hollow base
portion of the bowl. A comparatively dense, water immiscible
liquid, e.g., a halocarbon oil, is added to the sedimented blood
under the same dynamic conditions to displace plasma centripetally
and upwardly through the neck portion 4 of the sedimentation bowl.
The volume of displacing liquid is predetermined to slightly exceed
the total volume of the measuring system defined by chambers 10 and
passageways 14, in order that the measuring system will fill, yet
not overflow in volume exceeding that of the overflow chamber 15.
The displaced plasma spills over the top of neck portion 4 and is
caught within distribution manifold 9. The plasma then passes
through inlet ports 11 into plasma measuring chambers 10 and
corresponding passageways 14 until it reaches the limiting
centripetal level as defined by plasma overflow passagway 16.
Excess plasma flows through overflow passageway 16 into the
overflow chamber 15. The thus measured plasma subvolumes are
displaced from the measuring chambers 10 and passageways 14 into
respective sample analysis cuvettes by intermittent application of
air pressure to the open center portion of capping plate 8, while
maintaining rotation of the entire rotor assembly at about 1000
RPM. It is necessary to predetermine the combined volume of reagent
and plasma samples to be sufficient for photometric measurement,
without overfilling the sample analysis cuvettes to the point where
liquid could be lost by way of the cleanout passageways 17.
The above described preferred embodiment and method of operation is
intended to be illustrative and should not be interpreted in a
limiting sense. For example, particulate suspensions other than
whole blood could be processed to remove particulates and the
clarified supernatant analyzed. Also, the particular manner in
which reagents are loaded into the sample analysis cuvettes could
differ from that illustrated in that separate reagent loading
cavities could be provided which communicate by means of suitable
passageways with respective sample analysis cuvettes. It is
intended rather, that the invention be limited in scope only by the
following claims.
* * * * *