U.S. patent number 3,713,775 [Application Number 05/048,386] was granted by the patent office on 1973-01-30 for centrifuge clinical chemistry analysis system.
This patent grant is currently assigned to Bio-Dynamics, Inc.. Invention is credited to William David Schmitz.
United States Patent |
3,713,775 |
Schmitz |
January 30, 1973 |
**Please see images for:
( Certificate of Correction ) ** |
CENTRIFUGE CLINICAL CHEMISTRY ANALYSIS SYSTEM
Abstract
Medical testing apparatus including a centrifuge with a series
of cuvettes received therein. The cuvettes may be discrete units or
arranged in groups which make up cassettes. Each of the cuvettes
has a test chamber or reaction chamber into which reagents and
specimen pass during the centrifuging operation. The reagents are
contained prior to centrifuging in plastic bags which include
intentionally weak seams designed to fail during centrifuging and
to permit the reagents to flow into the reaction chamber. The
specimen is contained within a pipette tip closed by a cap. The cap
is also designed to fail or, in other words, be centrifuged off of
the pipette tip in order to permit the blood serum or plasma in the
pipette tip to flow past the cap and into the reaction chamber
after the red blood cells have been packed down into the cap by the
centrifuging operation. After centrifuging, the cuvettes can be
removed from the centrifuge and placed into a photometer to
determine the amount of light passed or the amount of light passed
can be determined directly while the cuvettes are being spun or
turned in the centrifuge by a photometer.
Inventors: |
Schmitz; William David
(Indianapolis, IN) |
Assignee: |
Bio-Dynamics, Inc.
(Indianapolis, IN)
|
Family
ID: |
27542729 |
Appl.
No.: |
05/048,386 |
Filed: |
June 22, 1970 |
Current U.S.
Class: |
422/72; 229/69;
383/210; 494/1; 494/17; 422/915; 422/918; 206/223; 356/427; 494/10;
422/550 |
Current CPC
Class: |
B04B
5/0414 (20130101); B04B 5/0421 (20130101); B01L
3/5453 (20130101); B01L 3/5021 (20130101); B04B
9/10 (20130101); G01N 21/07 (20130101); B04B
2007/025 (20130101); G01N 2035/0436 (20130101); Y10S
215/90 (20130101) |
Current International
Class: |
B04B
5/04 (20060101); B04B 5/00 (20060101); B04B
9/10 (20060101); B04B 9/00 (20060101); B01L
3/14 (20060101); G01N 21/03 (20060101); G01N
33/483 (20060101); G01N 21/07 (20060101); G01N
35/04 (20060101); B04b 009/10 (); G01n 021/24 ();
G01n 033/16 () |
Field of
Search: |
;23/253,230,259,292
;356/196,197,198 ;233/26,24 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wolk; Morris O.
Assistant Examiner: Reese; R. M.
Claims
The invention claimed is:
1. Test apparatus comprising a pipette tip, a cap on said pipette
tip, means for housing said pipette tip and cap, means for
centrifuging said pipette tip and cap and housing means at a first
speed until blood contained in said tip and cap is spun down into
its red cell fraction and its serum or plasma fraction and for then
increasing the speed of said centrifuging to a second speed
sufficiently fast to cause said cap to fly off of said tip and at
least a portion of said serum or plasma fraction to move past said
cap, said cap gripping said pipette tip with sufficient force to
remain thereon at said first speed but with insufficient force to
remain thereon at said second speed.
2. Test apparatus comprising a housing having a test chamber within
which a test reaction is carried out, means for centrifuging said
housing, a reagent container received within and carried by said
housing, said reagent container having a closure of pretermined
strength sufficiently weak to fail and open under the action of
said centrifuging means to permit flow of reagent from said reagent
container into said test chamber.
3. Test apparatus as defined in claim 2 additionally comprising a
chassis projecting into said housing and holding said reagent
container against said housing, a pipette tip mounted on said
chassis and extending into said chassis, a cap on said pipette tip,
said chassis having a hollow interior therein whithin which said
cap is received and is movable from an on the tip position to an
off the tip position, said means for centrifuging being operable at
a first speed at which blood contained in said tip and cap is spun
down into its red cell fraction and its serum or plasma fraction
and at a second speed at which said cap comes off said tip and
moves in said chassis to said off-the-tip position, said chassis
having an open end into which said hollow interior opens and which
leads into said test chamber, said chassis having grooves opening
into said hollow interior and permitting flow of serum or plasma
past said cap through said open end into said test chamber.
4. The test apparatus of claim 3 wherein said housing is a cuvette
having a reference chamber alongside said test chamber, photocell
means and light source means, said means for centrifuging being
operable to rotate said cuvette repeatedly between said photocell
means and said light source means in such a manner that said
reference chamber and said test chamber are exposed in order.
5. The test apparatus of claim 4 wherein said reagent container is
a flexible bag having a plurality of compartments therein, said bag
having some of said compartments positioned to discharge into said
test chamber and another of said compartments positioned to
discharge into said reference chamber.
6. Test apparatus comprising a housing having a test chamber
adapted to receive a specimen and reagents, said housing being
adapted to be received in a centrifuge for centrifuge action
thereon, a chassis member received in said housing, a pipette tip
received in said chassis member, a cap on said pipette tip, reagent
bags held between said housing and chassis, said cap being
sufficiently securely attached to said tip to hold onto said tip
while a blood specimen in said cap and tip is spun down into red
blood cells and serum or plasma, said cap being sufficiently
loosely attached to allow said cap to come off said tip under
increased centrifuge action, said chassis member having a hollow
interior therein within which said cap is movable from an on the
tip position to an off the tip position, said chassis member having
grooves opening into said hollow interior permitting flow of serum
or plasma past said cap into said test chamber.
7. Test apparatus comprising a cuvette having a test chamber within
which a test reaction is carried out, said cuvette also having a
reference chamber positioned alongside said test chamber, means for
centrifuging said cuvette, photocell means and light source means,
said centrifuging means being arranged to rotate said cuvette
repeatedly between said photocell means and said light source means
in such a manner that said reference chamber and said test chamber
are exposed in order.
8. Test apparatus comprising a pipette tip, a cap on said pipette
tip, means for housing said pipette tip and cap, means for
centrifuging said pipette tip and cap and housing means until blood
contained in said tip and cap is spun down into its red cell
fraction and its serum or plasma fraction and for then increasing
the speed of said centrifuging sufficiently to cause said cap to
fly off of said tip and at least a portion of said serum or plasma
fraction to move past said cap, said housing means including a
chassis, said pipette tip being mounted on said chassis so as to
extend into said chassis with said cap on the portion of said tip
which projects into said chassis, said chassis having a hollow
interior therein within which said cap is received and is movable
from an on the tip position to an off the tip position, said
chassis interior being formed with a shoulder which provides the
limit of movement of said cap when said cap moves into said off the
tip position, said shoulder being closely spaced to said tip to
prevent splashing of blood during said cap movement, said chassis
having grooves opening into said hollow interior and permitting
flow of serum or plasma past said cap.
9. Test apparatus comprising a container, a cap on said container,
means for housing said container and cap, means for centrifuging
said container and cap and housing means at a first speed until a
specimen contained in said container and cap is spun down into a
first fraction and a second fraction and for then increasing the
speed of said centrifuging to a second speed sufficiently fast to
cause said cap to fly off said container and at least a portion of
said second fraction to move past said cap, said cap gripping said
container with sufficient force to remain thereon at said first
speed but with insufficient force to remain thereon at said second
speed.
10. Test apparatus comprising a housing having a test chamber
adapted to receive a specimen and reagents, said housing being
adapted to be received in a centrifuge for centrifuge action
thereon, a chassis member received in said housing, a container in
said chassis member, a cap on said container, reagent bags held
between said housing and chassis, said cap being sufficiently
securely attached to said container to hold onto said container
while a specimen in said container and cap is centrifuged at a
first speed and spun down into a first fraction and a second
fraction, said cap being sufficiently loosely attached to allow
said cap to come off said container under increased centrifuge
action, said chassis member having a hollow interior therein within
which said cap is movable from an on the container position to an
off the container position, said chassis member having grooves
opening into said hollow interior permitting flow of a portion of
said specimen past said cap into said test chamber.
11. The test apparatus of claim 10 wherein said reagent bags have a
closure of predetermined strength sufficiently strong to remain
closed at said first speed but sufficiently weak to fail and open
under said increased centrifuge action to permit flow of reagent
from said reagent bags into said test chamber.
12. Test apparatus for spinning down blood into a first red cell
fraction and a second serum or plasma fraction and for moving at
least a portion of said second fraction away from said first
fraction which comprises a container, a cap on said container, a
housing for said container and cap, said container being mounted on
said housing, means for centrifuging said housing and container at
a first speed and for then increasing the speed of said
centrifuging to a second speed, said cap gripping said container
with sufficient force to remain thereon at said first speed but
with insufficient force to remain thereon at said second speed.
13. The test apparatus of claim 12 wherein said means for
centrifuging rotates said housing about an axis with said container
located between said axis and said cap whereby said cap moves
radially outwardly off of and away from said container when said
means for centrifuging increases speed to said second speed.
14. The test apparatus of claim 13 wherein said housing has a test
chamber, said test apparatus further including means for retaining
said cap and container between said axis and said test chamber when
said means for centrifuging centrifuges said housing and
container.
15. Test apparatus comprising a housing having a test chamber
adapted to receive a specimen and reagents, said housing being
adapted to be received in a centrifuge for centrifuge action
thereon, a chassis member received in said housing, a container in
said chassis member, a cap on said container, said cap being
sufficiently securely attached to said container to hold onto said
container while a specimen in said container and cap is spun down
into a first portion and a second fraction, said cap being
sufficiently loosely attached to allow said cap to come off said
container under increased centrifuge action, said chassis member
having a hollow interior therein within which said cap is movable
from an on-the-container position to an off-the-container position,
said chassis member having a passage opening into said hollow
interior permitting flow of a portion of said specimen past said
cap into said test chamber.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to testing apparatus and finds application
in medical testing apparatus.
2. Description of the Prior Art
There is available in the prior art various devices and procedures
for facilitating the running of medical tests. Certain devices and
procedures marketed by applicant's assignee pre-package some of the
reagents for a given test in the test cuvette and precalibrate the
meter used in the test. Other devices separate the test specimens
by bubbles and move the test specimens along a tube whereby
sequential testing is accomplished in a completely automatic
fashion. These devices are subject to certain disadvantages. For
example, there is presently no easy and convenient means and method
for separating serum or plasma from the blood for use in the test
procedure. The present standard procedure is to preprocess the
blood in a conventional centrifuge. Also the above mentioned
"bubble" separation test procedure is a very expensive device which
is only appropriate in the larger laboratories and hospitals where
substantial numbers of tests are carried out in a given period of
time.
Certain other prior art is disclosed in the following articles:
"Analytical Techniques for Cell Fractions" from Analytical
Biochemistry 28, pp. 545-562 (1969); "Computer Interfaced Fast
Analyzers" From Science, Oct. 17, 1969, Volume 166, Number 3903;
and "Analytical Techniques for Cell Fractions" from Analytical
Biochemistry 23, pp. 207-218 (1968) all of which relate to the
simultaneous use of a centrifuge and a photometer. Other prior art
is disclosed in the following U. S. Pat. Nos.:
2,663,461 Brown Dec. 22, 1953
2,861,572 Hind et al. Nov. 25, 1958
2,984,146 Kwart et al. May 16, 1961
3,026,764 Allen et al. March 27, 1962
3,050,239 Williams, Jr. Aug. 21, 1962
3,344,702 Wood et al. Oct. 3, 1967
3,415,627 Rait Dec. 10, 1968
3,452,924 Schultz July 1, 1969
3,477,822 Hamilton Nov. 11, 1969
3,481,712 Bernstein et al. Dec. 2, 1969
3,497,320 Blackburn et al. Feb. 24, 1970
SUMMARY OF THE INVENTION
One embodiment of this invention might include medical test
apparatus comprising a housing having a test chamber within which a
test reaction is carried out, means for centrifuging said housing,
a reagent container received within said housing and carried by
said housing in spaced relation to said test chamber, said reagent
container having a closure of predetermined strength sufficiently
weak to fail and open under the action of said centrifuging means
to permit flow of reagent from said container into said test
chamber. The embodiment may also include a pipette tip and a cap on
said pipette tip. The centrifuging means is operated to cause the
red blood cells to be spun down into the cap. The speed of the
centrifuge is then increased causing the cap to fly off the pipette
tip and the serum in the tip to pass into the test chamber.
This invention also relates to a complete system for simultaneously
and automatically processing a plurality of photometric chemical
tests. Each unit test cell or cuvette is self contained with
pre-packaged reagents. The general object of this invention is to
overcome a major deficiency in the prior art by providing a means
of processing whole blood directly, as an integral part of the test
cycle. An advantage is that this invention also provides a means of
adapting most of the presently developed photometric clinical
chemistry procedures which are designed for use with preprocessed
serum or blood plasma, to whole blood procedures by a mechanical
technique. This greatly reduces time required for testing, allows
the use of extremely small amounts of blood (in the 25 micro-liter
range) and significantly reduces the level of operator skill
required. A second area of major improvement over the prior art is
the pre-packaging of all reagents in separate cells of the reaction
cuvette assembly. All of the critical dispensing of reagents is
carried out in the production facility eliminating the need for the
complex reagent dispensing and handling system presently built into
automatic clinical analyzer systems in common use today. Because of
this the cost and maintenance requirements of the instruments can
be reduced and the ability to maintain accuracy improved.
Objects of the invention are to provide an improved test system and
apparatus; to provide medical test apparatus which does not require
a highly trained operator; to provide medical test apparatus
capable of preprocessing whole blood directly as an integral part
of the test procedure; to provide medical test apparatus which
simplifies maintenance in the field because no bulk reagents are
dispensed; and to provide medical test apparatus making possible
use of a form of double-beam spectrophotometry technique to cut
down error because of change in light source intensity.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a cassette carrier;
FIG. 2 is a perspective view of a pipette and a sample tube;
FIG. 3 is a perspective view of the pipette and a cassette;
FIG. 4 is a perspective view of a centrifuge;
FIG. 5 is a longitudinal sectional view of an assembly including a
curvette, a chassis, a pipette tip, a reagent containing bag, and a
cap;
FIG. 5A is a perspective fragmentary view of the structure of FIG.
5 but showing the cap thereof in a different operating
position;
FIG. 6 is a fragmentary perspective view of the cuvette, the
cassette carrier, and a photocell arrangement;
FIG. 7 is an enlarged (as compared to FIG. 5) side elevation of the
chassis;
FIG. 8 is an end elevation of the structure illustrated in FIG.
7;
FIG. 9 is a section taken along the line 9--9 of FIG. 8;
FIG. 10 is an enlarged top plan view of the cuvette;
FIG. 11 is a side elevation of the structure illustrated in FIG.
10;
FIG. 12 is an end elevation of the structure illustrated in FIG.
11;
FIG. 13 is an enlarged side elevation of the pipette tip;
FIG. 14 is an enlarged plan view of the reagent containing bag;
and
FIG. 15 is a side elevation of the structure illustrated in FIG.
14.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, a sample tube 30 containing whole blood is
illustrated and carries information on the label 31 concerning the
contents and may be sealed or closed by a cap (not shown). In FIG.
3, a cassette 35 is illustrated which includes four cuvettes 36
connected together by plastic material 37. The top openings 38 in
the cuvettes are sealed by a tear strip seal (not shown). Also the
cassette is provided with a data card 33 carrying information
concerning the contents of the cassette. The plastic material 37 is
bendable in the manner illustrated in FIG. 1 to permit the cassette
35 with its cuvettes 36 to be mounted or received within a cassette
carrier 40 illustrated in FIG. 1. The cassette carrier 40 is shown
in FIG. 1 with its top removed and as including a container 41
having a flat base 42 and upturned cylindrical side-walls 45.
Mounted on the base 42 are retainer clips 46 which function to
yieldably receive and resiliently hold in position the cuvettes 36
of the cassette 35. As illustrated, the flat bottom 42 of the
carrier includes a central circular opening 47 with a keyway 50
therein which permits locking of the cassette carrier in place in a
centrifuge for rotation of the carrier and centrifuging of the
contents thereof.
In FIG. 2, there is shown a pipette 51 which includes a pipette
pump 52 and a pipette tip or container 55. The pipette is disclosed
in the co-pending application for U. S. Letters Pat., Ser. No.
864,280, of Hinchman, Sommerville and Schmitz, assigned to the same
assignee as the present invention. It is sufficient for present
purposes to state that the pipette pump 52 functions to always draw
in and dispense an equal volume of blood or other substance by
suitable operation of the plunger 54. FIG. 13 shows in detail the
construction of the pipette tip 55 as including a hollow interior
56 which has a tapered portion 57 facilitating attachment of the
pipette tip 55 to the pipette pump. As shown in FIG. 3, the pipette
pump 52 has an O-ring 60 mounted thereon which assists in
effectively connecting the pipette tip 55 to the pump 52 in a leak
proof manner. The O-ring seats in the cylindrical portion 58. The
hollow interior 56 of the tip includes tapering portion 56' which
tapers gradually from its larger end adjacent the cylindrical
portion 58 down to the other smaller end 59 of the pipette tip 55.
There is formed at that other end 59 reduced cylindrical portion 63
having a shoulder 61 for reception of a cap 62 shown in FIGS. 5 and
5A. In use the pipette 51 is inserted into the cap 62 for attaching
the cap to the reduced diameter cylindrical portion 63 and abutting
the shoulder 61 of the pipette tip. The cap 62 is cylindrical and
has a closed end 64' in addition to the open end 64.
Referring now to FIGS. 10, 11 and 12, a cuvette 36 is illustrated
in more detail as including a generally cylindrical portion 100 and
a flat portion 101. The cylindrical portion 100 has a generally
cylindrical hollow interior 102 into which the chassis 105 of FIGS.
7, 8 and 9 is projected in operation of the present apparatus as
described in more detail below. The flattened portion 101 of the
cuvette has formed therein a test or reaction chamber 105' and a
reference chamber 106 which are separated by a partition 107.
Referring to FIGS. 7, 8 and 9, the chassis has a hollowed-out
interior 110 formed with a shoulder or tapered portion 111 which
functions to prevent further movement rightwardly as viewed in
FIGS. 7 and 9 of the cap 62. The cap 62 is so sized as to be easily
slidable in the hollow interior 110 without being loosely received
whereby the cap will always have its closed end 64' projected
toward the flattened end of the cuvette as shown in FIGS. 5A and 5.
The hollow interior 110 is also formed with inwardly opening
grooves 112 which permit blood (serum) or plasma to run past the
cap rightwardly out of the open end 115 of the hollow interior 110.
The chassis 105 also includes outwardly projecting ribs 116 which
function to engage and hold the flexible plastic container of FIG.
23 between the chassis and the cuvette. It will be noted that the
grooves 112 lead into grooves 114 which open into the tapered
portion 111.
Referring now to FIGS. 2 through 6, the test procedure of the
present invention is illustrated as including the placing of the
pipette tip 55 in the blood contained within the container 30 for
the obtaining of a sample of blood. This blood sample is precisely
measured by operation of the pipette 51. The pipette is so operated
as to withdraw the blood contained within the pipette tip slightly
away from the tip and then the end of the pipette tip is wiped off.
The end of the pipette is then inserted in a cap 62 in such a
manner that the shoulder 61 abuts the cap. The pipette tip 55 with
its cap 62 thereon is then inserted into the cuvette 36 of the
cassette in the manner shown in FIGS. 3 and 5A.
As suggested by the drawings, quite a number of blood samples can
be carried by the cassette carrier at one time. The purpose of the
cassette is to segregate four samples of blood of one person so
that four different tests can be run on that blood at one time. Of
course, various other person's cassettes can also be tested as
suggested by the additional retainer clips 46 of the cassette
carrier as shown in FIG. 1. The manner in which the pipette tip 55
with its cap thereon seats within the cuvette is illustrated in the
cut-away FIG. 5A view. As illustrated the cap is press fitted on
the reduced cylindrical projection 63 and abuts the shoulder 61.
The cap is spaced from tapered portion 111. FIGS. 5 and 5A show in
addition a reference component bag or container 200 and a reagent
bag or container 201. As shown in FIG. 23 the reagent bags 201 and
the reference component bag 200 are joined together as a part of
the four bag group 202. These four bags are folded or cupped around
the exterior of the chassis 105 so that the dividing areas 205
between the bags of the group contact the projections 116
illustrated in FIGS. 7, 8 and 9.
These projections 116 hold the container 202 against the inside
wall of the cuvette 100. The group 202 of bags is so constructed
that one edge 206, 207, 208 and 209 of the group of bags 202 is
weaker than all the other edges thereof so that under centrifugal
action the edges 206, 207, 208 and 209 fail, permitting dispensing
of the contents of the bag by centrifugal force into the reaction
chamber and the reference chamber. The bags 201 and 200 are so
located that all of the bags 201 empty into the reaction chamber
and only the bags 200 empty into the reference chamber. The
weakness of the edges 206, 207, 208 and 209 is also designed so as
to fail at a certain speed of the centrifuge, in other words, upon
a certain number of "g's" being exerted on an edge. If desired, the
edges can be designed to fail at different weaknesses. In this
manner, the various reagents or contents of the bags can be
discharged in order so as to cause the test reaction to be in
accordance with predetermined standard test procedures.
Returning to the description of test procedure, the cassette with
its four cuvettes and four pipette tips is then loaded into the
centrifuge 300 as shown in FIG. 4 after the top 301 has been placed
on the cassette carrier 40. The cassette carrier has apertures 302
in its base 42 as well as apertures 305 in its top. The apertures
302 and 305 are each aligned with a respective one of the flattened
portions 101 of the cuvettes. The centrifuge 300 is capable of
various speeds of rotation up to 10,000 rpm as desired by the
operator. In one embodiment of the invention as shown in FIG. 6 a
lamp 306, photocell 307 and light shield 310 with slit 311 are
built into and are a part of the centrifuge. Another embodiment of
the invention might include a standard colorimeter separate from
the centrifuge and usable only after the centrifuging operation has
been carried out. In such an embodiment the centrifuge would not
incorporate a colorimeter or photocell.
It should be understood that, if the photometer is a part of the
centrifuge and if readings are taken while the centrifuge is
rotating, suitable electronic circuitry must be incorporated for
separating the signals received from the various cuvettes. In such
operation the reference chamber 106 provides the advantage of
double beam spectrophotometry by making possible with a single beam
a comparison of the absorbancy of a reference solution and a
sample. This comparison is made over a time interval which is short
relative to the rate of change in intensity of light source thus
providing the advantage of double beam spectrophotometry.
In the test procedure the operator controls or may control the time
at which various events occur. Thus, the first step in the process
is the spinning down of the blood which may occur for example at
1,800 rpm because of the small quantity of blood being spun down.
Next the operator speeds up the centrifuge to the speed at which
the cap 62 comes off of the centrifuge tip for example at 3,000
rpm. Further speeding up of the centrifuge to 8,000 rpm causes the
first of the bags 200 and 201 to fail and all bags 200 and 201 have
failed at 10,000 rpm. Various other bag failure speeds can be
selected in order to accomplish the test procedure and timing
desired. Alternatively, the centrifuge might be programmed to
automatically reach the various speeds desired at various times
desired so as to make the procedure entirely automatic.
FIG. 5 shows the cuvette just after the speed has been reached at
which the cap is forced off of the pipette tip. Also shown is the
discharging of the reagent bags into the reaction chamber 105 and
the reference chamber 106. As illustrated, the cap 62 moves
leftwardly against the tapered surface 111. Prior to the leftward
(as illustrated) movement of the cap in the hollow interior 110 of
the chassis, the red blood cells 400 in the blood have
substantially all moved into the cap 62 so that serum fills the
rest of the cap and also extends into the pipette tip. When the cap
comes off the pipette tip and moves the relatively short distance
from the tip to the tapered surface 111, the hollow interior 110
(which is basically cylindrical where the cap is) guides the cap
preventing any of its contents from spilling. The substantial "g"
forces acting on the cap and its contents level off the top (or
rightward as illustrated) surface of the liquid in the cap so that
the total contents of the cap are precisely determined. Also the
cap moves only a very short distance so that splashing does not
occur.
The cap might have a capacity of, for example, 0.0125 ml while the
change of blood in the pipette tip and cap is, for example, 0.025
ml. During spinning down of the blood the red blood cells occupy
perhaps 0.0833 of volume at the bottom (or leftward end as
illustrated) of the cap. Thus, serum occupies the remainder of the
contents of the cap as well as extends up into the pipette tip.
Therefore, the liquid which flows into the reaction chamber is
serum from the tip. This serum moves out of the pipette tip and
through the grooves 112 and 114 and through the open end 115 when
the cap comes away from the tip. The serum that flows in this
manner into the reaction chamber is a precise .0125 ml of liquid
because of the centrifugal force action.
While the invention has been disclosed and described in some detail
in the drawings and foregoing description, they are to be
considered as illustrative and not restrictive in character, as
other modifications may readily suggest themselves to persons
skilled in this art. For example, the photometer optics might be
built into the centrifuge in such a manner that, after the
reactions are completed, the centrifuge head is stopped and then
rotated by hand so as to successively position each cuvette into
the light beam for a reading. Also the blood specimen might be
diluted prior to placing the specimen in the pipette tip so as to
make possible use of existing test procedures instead of requiring
the setting up of new test procedures. In other words, the
quantities are scaled down in order to keep the balance and
therefore the same chemistries can be used.
Other applications of the invention might include analytical tests
for water and air pollution, water treatment tests, as well as
industrial chemical testing.
* * * * *