Reagent pack and carousel

A multiple dose reagent pack and corresponding carousel for an automated analyzer are disclosed. The reagent pack contains a plurality of vial-receiving wells which receive and hold a plurality of reagent-containing vials to form a unitary reagent pack. The carousel contains a plurality of radially spaced compartments which are adapted to receive and hold either a reagent pack or a sample container. A corresponding plurality of reaction container openings are provided on the carousel. Reagent packs for specific assays can be selectively interspersed with sample containers in the compartments to provide a wide variety of test combinations.

FIELD OF THE INVENTION 
This invention relates generally to carriers for transporting containers of 
fluids such as reagents or biological samples and to diagnostic instrument 
components designed to retain the carriers in close proximity to the area 
where an immunoassay using the transported fluid is conducted. More 
specifically, this invention relates to a pack that carries multiple 
reagent containers and to a carousel adapted to receive and hold such 
packs and biological sample containers for use by an automated clinical 
analyzer in conducting immunoassays. 
BACKGROUND OF THE INVENTION 
Typically, samples of bodily fluids such as serum, plasma, urine, and the 
like, are assayed for the presence of analytes such as drugs, viruses, or 
bacteria by reacting the samples according to a specific test protocol 
with specific reagents which are selected to identify a particular 
analyte. The protocol specifies the sequence in which sample and reagents 
are to be introduced, the timing for the introduction of sample and 
reagents, the volumes of each to be used, and other conditions to be 
controlled, such as temperature. The resulting reaction mixture is 
typically allowed to incubate for a predetermined time and is then read, 
optically or otherwise, to determine the presence and concentration of the 
specific analyte which the assay is designed to identify. In general, 
processes and apparatuses for preparing and reading immunoassays are well 
known. 
Automated clinical analyzers are capable of performing immunoassays on an 
entire batch of samples simultaneously. In some types of known analyzers, 
such as the well-known TDx.RTM. Clinical Analyzer manufactured by Abbott 
Laboratories of North Chicago, Ill., a batch of sample containers are 
mounted radially about a rotatable carousel together with a corresponding 
number of reaction containers. The carousel is then mounted inside the 
analyzer. Inside the analyzer, the carousel rotates stepwise to move each 
corresponding sample container and reaction container pair first to a 
position adjacent a preparation station, and then to a second position 
adjacent a reading station. A mechanical apparatus having pipetting means 
and typically operating under program control is located in proximity to 
the preparation station. Also located in proximity to the preparation 
station are a plurality of reagent containers which contain the reagents 
required to perform a specific immunoassay on the batch of samples 
contained in the sample containers. The reagent containers may be 
individual containers or may be configured as an integrated pack. 
At the preparation station, the mechanical apparatus and pipetting means 
operate to access and transfer volumes of sample from a sample container 
and reagents from the reagent containers into a reaction container 
according to the protocol established for the specific assay. When the 
mechanical apparatus completes the preparation of the reaction mixture 
according to the test protocol, the carousel rotates, positioning the next 
corresponding sample container and reaction container pair adjacent the 
preparation station, and moving the previous pair toward the reading 
station. Known carousels typically hold between 20 and 25 containers. 
One limitation of a number of these analyzers is that they are capable of 
performing only one assay at a time on each batch of samples on the 
carousel. In order to perform a different assay, it is necessary to 
physically remove the reagent containers either individually or as a pack 
from the analyzer and replace them with different reagent containers or a 
different pack for the assay to be run. The requirement of changing 
reagent packs for each assay has an adverse impact on the throughput of 
the analyzer. Where multiple assays are to be performed on the same batch 
of samples or on different samples, the requirement of changing reagent 
containers for each assay has an even more severe adverse impact on the 
throughput of the system. Decreased throughput increases both the time and 
cost associated with such assays. 
One approach to solving this problem of some known analyzers has been to 
provide unit dose or unitized reagent containers each containing an 
aliquot or reagents sufficient to carry out a specific assay on one 
sample. These containers are mounted on the analyzer carousel in positions 
corresponding to each sample container. With utilized reagent containers, 
different immunoassays can be carried out on each sample. For example, one 
sample can be assayed for a certain class of drugs, the next for the 
presence of a strain of virus, the next for a certain class of bacteria, 
and so forth. 
The unit dose approach has not provided a completely satisfactory solution 
to the problems of the prior art. First, it is relatively expensive to 
manufacture and use unit dose containers, which are limited to use with 
one sample. Second, it is time consuming. This drawback is particularly 
noticeable where only one or a small number of different assays are to be 
conducted on the samples in a particular batch. With the relatively large 
number of sample and unit dose reagent containers that must be mounted on 
each carousel, the risk of inaccurate delivery of a sample to a specific 
unitized reagent container is increased. This increases the risk of 
performing the wrong test on a sample. 
In view of the foregoing limitations and drawbacks of the prior art, it is 
the primary objective of the present invention to provide a multiple dose 
reagent pack which can be expediently mounted on a carousel with a 
plurality of sample containers to provide reagents for conducting 
immunoassays of a plurality of such samples. It is a related object to 
provide a carousel which is adapted to hold a plurality of such multiple 
dose reagent packs interspersed with such sample containers to flexibly 
provide reagents for performing the same or different assays on the same 
or different samples. It is a significant advantage of the invention that 
flexibility is provided to perform a selected plurality of different 
assays on the same or different samples and to selectably vary the number 
of different assays performed on each sample while maintaining high 
throughput levels and reducing the requirement for physical interaction 
with the analyzer and the carousel. 
SUMMARY OF THE INVENTION 
The present invention seeks to overcome the foregoing limitations and 
drawbacks associated with the prior art by providing a multiple-dose 
reagent pack and a carousel for an automated clinical analyzer adapted to 
hold such packs together with a plurality of conventional sample 
containers which contain samples to be assayed by the analyzer. 
In one aspect, the invention comprises a reagent pack which includes a vial 
carrier having a plurality of vial receiving wells for containing a 
corresponding plurality of multiple-dose reagent-containing vials. In 
another aspect, the invention comprises a carousel for use with such 
reagent packs in an automated clinical analyzer. The carousel includes a 
base for rotatably mounting the carousel in the analyzer and a rack which 
is connected to the base and which has a plurality of predetermined 
mounting positions which are adapted to releasably mount the reagent packs 
in selected positions.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS 
Referring to the drawings, FIGS. 2 through 6 illustrate two preferred 
embodiments of the multiple dose reagent pack of the invention. Referring 
to both embodiments, the preferred reagent pack of the invention comprises 
in combination a vial carrier 50 and a plurality of reagent-containing 
vials 40 which are removably mountable therein. The vial carrier 50 is 
preferably manufactured of a suitable plastic such as an ABS or SAN 
plastic by conventional plastic molding techniques. 
Referring to FIGS. 3 and 4, one preferred embodiment of the vial carrier 50 
has three cylindrical vial receiving wells 58a-c. A second preferred 
embodiment has four such wells 58d-g. Each well 58a-g has a plurality of 
inwardly protruding vertical ribs 62 radially spaced about the inner wall 
thereof. The ribs 62 are adapted to provide a secure press fit with the 
outside surface of a vial 40 when the vial 40 is mounted in the well 
58a-g. The wells 58a-c and 58d-g are preferably arranged such that their 
centers are co-linear for reasons which will become apparent below. The 
wells 58a-c and 58d-g are also preferably arranged such that adjacent 
wells slightly overlap. Vertical, linear dividing walls 60 are provided to 
separate the adjacent wells. The linear dividing walls 60 slightly 
restrict the otherwise circular cross-sectional area of each of the wells 
function to press the outer surface of each vial 40 mounted in a well 
58a-g into pressing contact with each of the ribs 62 to provide a secure 
press fit therewith. 
A curved vertical retaining wall 54 is connected to the wells in each 
embodiment by a thin horizontal shelf 52. The radius of the retaining wall 
54 preferably is approximately equal to the radius of the outside rim of 
the corresponding carousel 70 which is described in detail below. The 
shelf 52, which is preferably co-planer with the open tops of the wells, 
diverges outwardly, starting at the third well 58c, 58f, from the 
retaining wall 54 symmetrically on both sides of the wells as illustrated 
in FIGS. 4 and 6. The shelf 52 extends in the direction of a line through 
the centers of the wells a sufficient distance beyond the well 58a, 58d 
nearest the retaining wall 54 to form a gap 53 therebetween. The shelf 52 
preferably intersects the retaining wall 54 a short distance below the top 
thereof, thereby forming a tab 55. Both the tab 55 and the shelf 52 
provide convenient means for handling the reagent pack 50 without touching 
the vials 40, thus minimizing the risk of contamination of reagents in the 
vials 40 by a human operator. The shelf 52, retaining wall 54, and a gap 
53 also cooperate with the carousel 70 as described in detail below to 
securely support and hold the reagent pack 50 therein. 
Referring to FIGS. 3-6, the vial carrier 50 includes a projecting vertical 
ridge 51 at the inner end of the well 58c, 58g furthest from the retaining 
wall 54. The ridge 51 prevents the inadvertent reverse placement of the 
carrier 50 in the carousel 70 by providing an offset between the wells 
58a-c and 58d-g of the carrier 50 and corresponding openings of the 
carousel 70, which is described below, so that the carrier 50 will not 
correctly engage the carousel 70 in a reverse position. It will be 
appreciated by those skilled in the art that other structures may also be 
used to provide an offset. For example, a "Y" shaped or "V" shaped ridge 
could be provided to generate an offset at two points with respect to the 
openings of the carousel 70 instead of one. 
The outer surface 56 of the vertical retaining wall 54 and tab 55 provides 
a location for labelling means which preferably includes both operator 
readable identifying information in the form of graphics or alphanumeric 
designations, for example, and analyzer readable information such as an 
optical bar code. The labelling means is advantageously used to identify 
to the operator and the analyzer the assay which the reagent pack 50 is 
intended to perform. The labelling means also provides a convenient means 
for tracking a test sample through the entire analysis procedure with the 
analyzer instrument. 
In both preferred embodiments, the wells 58a-c and 58d-g are adapted to 
hold plastic reagent-containing containing vials, similar to the vial 40 
partially illustrated in perspective in FIG. 2. The vials 40 are 
preferably formed at minimal cost of a thin, flexible plastic by 
conventional plastic molding techniques. Alternatively glass or other 
vials can be used. The vials 40 are generally cylindrical in shape and 
have a vertical dimension sufficient to elevate the neck and opening of 
the vial 40 above the opening of a well 58a-g for ease of access when the 
vial 40 is mounted in the well 58a-g. Each vial 40 preferably has a 
capacity of approximately 2.5 milliliters of a selected reagent, which is 
typically sufficient to perform assays on approximately 50 samples. The 
vials 40 are suitably provided with conventional threaded or capped 
closures, and may, after being opened, be resealed with a vial seal such 
as the vial seal described in the co-pending application entitled "Vial 
Seal" which was filed in the name of Walter Jordan on the same date as 
this application and which is commonly assigned with this application. 
Although it would be possible to form the vials 40 integrally with the 
vial carrier 50, it is preferred that the two components be embodied 
separately. Separate vials 40 are easier to fill and avoid the risk of 
contaminating the reagent in one vial with reagents from adjacent vials 
during the filling process. Also, in the preferred embodiment, both the 
vials 40 and the carrier 50 are disposable as a single unit when the 
reagents in the vials 40 are expended. 
With the foregoing preferred embodiments, a supplier of reagents can 
economically provide reagents for specific assays to the operator of an 
automated analyzer in a convenient unitary reagent pack. Thus, for 
example, the operator can purchase reagent packs for cocaine or other drug 
tests, and the packs received by the user will contain all the necessary 
reagents for each desired assay already present in vials 40 mounted in a 
carrier 50. 
Generally, the three vial embodiment of the reagent pack is best suited for 
use in assays of the type requiring a pretreatment reagent usually used to 
unbind the analyte of interest from certain proteins in the sample, and 
analyte compliment for binding the unbound analyte, and a specifically 
tagged or labelled tracer reagent for indicating the presence of the 
analyte of interest. Each of the required reagents is contained in one of 
the vials 40 of the reagent pack. 
The four vial embodiment is particularly well suited for use in certain 
assays of the type described above but which are particularly sensitive to 
carryover of any reagent, for example by pipetting means of an analyzer, 
from one reagent vial to another. Examples include assays for marijuana, 
cocaine, and amphetamines. For such assays, the fourth vial of the pack is 
advantageously provided to contain a wash or buffer reagent that can be 
used to rinse the pipetting means after it accesses each reagent. 
Additional features and advantages of the invention are provided by a 
carousel 70 for an automated analyzer as illustrated in FIGS. 1, 2, 8, and 
9. The carousel 70 is advantageously adapted to receive and hold a 
selected plurality of reagent packs 50 of the invention in selected 
positions of the carousel 70 interspersed with sample containers 
containing samples to be tested. The carousel 70 also provides means for 
ensuring that a reagent pack 50 can be mounted therein in but a single 
predetermined orientation. As described previously, ridge 51 precludes 
reagent pack 50 from reverse placement in the carousel 70. Thus, the 
operator of an analyzer adapted to operate with the corresponding reagent 
pack 50 and carousel 70, can simply purchase or otherwise obtain a reagent 
pack for a cocaine test, for example, mount it directly into the carousel 
70, and be assured that the appropriate reagents are present and arranged 
in the appropriate positions required by the analyzer to automatically 
perform the desired assay. The preferred carousel 70 also includes means 
to receive and hold a plurality of reaction containers. As will be seen, 
many testing combinations are thereby made possible and a great deal of 
flexibility is thereby provided. 
The carousel 70 generally comprises a circular rack 20 and a central base 
or support 30 which preferably are integrally formed of a suitable plastic 
such as ABS or SAN plastic using conventional plastic molding techniques. 
The rack 20 comprises a plurality of vertical dividing walls 26 which 
extend radially from the periphery of the central base 30 at regular 
intervals. Each dividing wall 26 is connected to the adjacent dividing 
walls by a horizontal support surface 22 which has a circular periphery 
and which is integrally formed with the rack 20. The support surface 22 
extends between the adjacent dividing walls 26 at a vertical elevation 
such that a small portion 27 of each wall 26 extends vertically above the 
support surface 22. A downwardly oriented, vertical edge or rim 23 is 
formed around the periphery of the support surface 22. 
The dividing walls 26, together with the support surface 22, vertically 
extending portions 27, and base 30 form a plurality of radially diverging 
compartments, each defining a mounting position on the carousel 70. Each 
compartment has a diverging lateral dimension corresponding to the 
diverging lateral dimension of the shelf 52 of a reagent pack 50. In each 
compartment, the support surface 52 has formed therein two generally 
circular, slightly overlapping openings 31 and 33 which correspond to and 
which are adapted to receive two of the vial receiving wells of a reagent 
pack 50. When a reagent pack 50 is mounted in a compartment, the two vial 
receiving wells 58a-b, 58d-e closet to the curved retaining wall 54 of the 
reagent pack 50 are captivated in the openings 31 and 33 and prevented 
from moving laterally or radially. The vial receiving well or wells 
furthest from the retaining wall 54 are supported on the top surface of 
the central base 30. In a three vial reagent pack the base 30 supports one 
well 58c. In a four vial reagent pack, the base 30 supports two wells 
58f-g. The gap 53 between the retaining wall 54 and the nearest vial 
receiving well 58a, 58d of the reagent pack 50 provides clearance for the 
portion of the support surface 22 between the opening 31 and outer edge 
23. The curved retaining wall 54 extends over and around the curved outer 
edge 23 of the support surface 22 and the two elements together with the 
gap 53 cooperate to prevent the reagent pack 50 from moving radially. The 
support surface 22 supports the bottom surface of the shelf 52 of the 
reagent pack 50. The diverging edges of the shelf 52 fit between and 
preferably abut the radially extending vertical sections 27 of the rack to 
facilitate mounting of a reagent pack 50 in a compartment and to prevent 
lateral movement of the pack 50 within the compartment. As previously 
mentioned, the ridge 51 on each reagent pack 50 provides an offset which 
prevents the reagent pack 50 from being mounted in a compartment with the 
ridge 51 facing toward the periphery of the rack 20. Thus in the preferred 
embodiment, the reagent pack 50 can only be mounted in a single 
orientation with the ridge 51 directed toward the central base 30. 
It is understood that the carousel 70 could be constructed with vial 
carriers formed integrally in predetermined compartments of the rack 20. 
However, such construction reduces the flexibility provided by the 
invention and is not preferred. 
The carousel 70 illustrated in FIGS. 1, 2, 8, and 9 includes a circular 
recess 25 formed on the central base 30. The recess 25 provides an 
advantageous location for the placement of identifying indicia such as a 
raised number (not shown) for each carousel position. Duplicate indicia 
(not shown) may also be provided along the periphery of the rack 20 
between the openings 31 and the outer edge 23. In an alternative 
embodiment (not shown), the recess 25 may be replaced by a vertical 
barrier to allow mounting of three vial reagent packs while preventing the 
mounting of four vial packs. 
The base 30 also has formed therein a plurality of reaction container 
receiving openings 29 corresponding in number to the number of rack 
compartments. The openings 29 radially spaced at regular intervals around 
the base 24 and the center of each opening 29 is aligned with the centers 
of the openings 31 and 33 of a corresponding rack compartment. Each 
opening 29 has formed in the inner surface thereof at least two fixed 
retaining projections 16 and 17. A locking mechanism comprised of a 
plurality of spaced spring fingers 41 corresponding to the number of 
openings 29 is integrally formed with a handle 42 of the carousel 70. The 
handle and locking mechanism are rotatably mounted on the base 30 so that 
the fingers 41 rotate when the handle 42 is moved. As seen in FIGS. 1 and 
9, when a finger 41 is rotated to a position opposite projections 16, 17 
the finger 41 functions to press the outer surface of a reaction 
container, which may be a conventional cuvette, into contact with the 
projections 16, 17 of the opening 29 to establish a secure press fit of 
the cuvette within the opening 29. The fingers 41 may also be rotated away 
from the openings 29 to allow insertion and removal of reaction 
containers. The fingers 41 preferably have the same construction as the 
fingers which perform the same function on the well known Abbott TDx.RTM. 
carousel. 
When a reagent pack 50 is mounted in a compartment of the rack 20, at least 
one of the vial receiving wells 58 sits over and covers the corresponding 
reaction container opening 29 so that no reaction container can be mounted 
in that mounting position of the carousel 70. In addition, as shown in 
FIGS. 1 and 9, the carousel 70 preferably has one mounting position that 
does not include a corresponding opening 29. This position defines a 
reference position for the analyzer which indicates that all samples have 
been tested. 
In addition to reagent packs, each compartment is also adapted to 
alternatively receive and hold a sample container adapted to contain a 
sample to be tested. In particular, the opening 31 and 33 of each 
compartment are preferably adapted to hold sample cups 45 of the type 
illustrated in FIG. 7 and in U.S. Pat. No. Des. 273,807 which issued to 
Holen on May 8, 1984. The preferred sample cups 45, like the preferred 
reagent pack 50, have sample-receiving wells 46 which are received within 
and held by the openings 31 and 33, a diverging shelf 47 which is 
supported by the support surface 22 of the rack, and diverging lateral 
sides which allow each cup 45 to be mounted in a compartment with a 
single, predetermined orientation. The sample cups 45 are thus held and 
secured against lateral and radial movement in the rack compartments 
similarly to the reagent packs 50 except that the sample cups 45 do not 
extend over the outer edge 23 of the rack 20. 
The underside of the base 30 of the carousel 70 is provided with a 
conventional support spindle receiving well (not shown) and a plurality of 
conventional drive slots (not shown) which are arranged radially around 
the circumference thereof. Such a well and such drive slots are well known 
to those skilled in the art and are commonly found on carousels of the 
type utilized in such well known automated analyzers as the Abbott 
TDx.RTM. analyzer. As is well known, the receiving well mounts the 
carousel 70 for rotation on a stationary spindle in the analyzer. The 
drive slotsd mate with a drive mechanism such as the teeth of a pinion 
gear attached to a stepper motor of the analyzer to rotate the carousel 70 
and thereby index each compartment between an assay preparation position 
and an assay reading position within the analyzer. Although the carousel 
drive and support elements of a typical automated analyzer have been 
briefly described to identify the environment of the carousel, these 
elements and the analyzer itself are beyond the scope of and do not form a 
part of the present invention. 
It should be apparent from the foregoing description of the preferred 
reagent packs 50 and corresponding carousel 70 that the invention provides 
a great deal of flexibility and many possible testing combinations. For 
example, reagent packs for cocaine, amphetamine, barbituate, and marijuana 
tests can be mounted in selected compartments of the rack with, for 
example, four compartments separating each pack as shown in FIG. 1. 
Although FIG. 1 shows only one sample cup per reagent pack for purposes of 
illustration, four sample cups containing samples of the same or of 
different groups of four persons could be selectively mounted in each of 
the four compartments adjacent the specific reagent packs. An entire 
battery of drug tests could then automatically carried out on the same or 
different four person groups. 
As another example, four identical reagent packs for a certain viral test 
can be mounted on the carousel in selected compartments with samples of 
different persons being mounted in intermediate compartments in the manner 
described above to automatically carry out an assay for the same virus on 
an entire batch of samples. Many other arrangements and combinations 
exist. 
What have been described are various aspects of certain reagent packs and a 
corresponding carousel which constitute presently preferred embodiments of 
the invention. It is understood that the foregoing description and 
accompanying illustrations are merely exemplary and are not to be taken as 
limitations on the scope of the invention, which is defined solely by the 
appended claims and their equivalents. Various changes and modifications 
to the preferred embodiments will be apparent to those skilled in the art. 
Such changes and modifications can be made without departing from the 
spirit and scope of the invention. Accordingly, it is intended that all 
such changes and modifications be covered by the appended claims and their 
equivalents.