US00862329lB2
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`12 United States Patent
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`10 Patent No.:
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`9
`9
`US 8 623 291 B2
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`Lee
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`(45) Date of Patent:
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`*Jan. 7, 2014
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`(54) MULTIPLE ANALYTE ASSAY DEVICE
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`(56)
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`References Cited
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`(76)
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`Inventor:
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`Jin P0 Lee, Carlsbad, CA (US)
`
`U-S- PATENT DOCUMENTS
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`11/1977 Jam“
`gzfiiirweiyaét al.
`6/1998 K_1imovet_a1.
`...............H 422/58
`(T:§l,%1i{I(1);;S:la1.
`2/2003 Lee
`4/2003 Lee et al.
`...................... .. 422/58
`5/2004 Lee etal.
`422/58
`3/2008 Lee ....... ..
`422/58
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`4056359 A
`2
`5,770,458 A
`Q1 4
`6,514,769 B2
`6,548,019 B1*
`6,730,268 B2*
`7,347,972 B1*
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`812025487 B2 *
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`6/2012 Lee ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~ 422/401
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`DE
`*
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`FOREIGN PATENT DOCUMENTS
`29702825
`*
`5/1994
`.
`.
`Clted by exammer
`.
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`Primary Examine’ Z LY1e.A1eXander
`(74) Attorney, Agent, or Firm — Bemd W Sandt
`
`( * ) Notice:
`
`Subject to any disclaimer, the term ofthis
`patent is extended or adjusted under 35
`USC. 15403) by 1444 days
`This patent is subject to a terminal dis-
`clalmer.
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`(21) App1.N0.; 11/650,230
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`(22)
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`Filed:
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`Jan. 5, 2007
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`(65)
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`Prior Publication Data
`US 2007/0128072 A1
`Jun. 7, 2007
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`Related U.S. Application Data
`(63) Continuation-in-part of application No. 10/019,570,
`filed as application No. PCT/US98/15359 on Jul. 14,
`1998, now Pat. No. 7,347,972.
`
`Int. Cl.
`G01N 33/48
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`(51)
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`(52)
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`(2006.01)
`422/401 422/420 422/430 436/164
`436/165
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`(58) Field of Classification Search
`USPC ................. .. 422/401, 420, 430; 436/164, 165
`See application file for complete search history.
`
`ABSTRACT
`(57)
`The present invention relates to an assay device capable of
`testing for multiple analytes such as drugs using individual
`test strips for each analyte.
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`9 Claims, 6 Drawing Sheets
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`1
`MULTIPLE ANALYTE ASSAY DEVICE
`
`This application is a continuation-in-part of Ser. No.
`10/019,570 filed Nov. 8, 2001 now U.S. Pat. No. 7,347,972,
`which is based on PCT application US98/15369 filed Jul. 22,
`1998.
`
`BACKGROUND
`
`1. Field of the Invention
`
`The present invention relates to methods and devices for
`assaying biological fluid samples. More particularly the
`invention relates to methods and devices for detecting ana-
`lytes, such as drugs, in urine.
`2. History of the RelatedArt
`In their most simple form, chromatographic analyte
`devices permit an assay to be performed in a single step
`(application of an analyte sample to the device) to producer
`visually observable assay results (such as those indicated by
`colored bars on the test strip). However a common limitation
`of such devices is that they can only be used to detect a single
`analyte, requiring that serial assay procedures be performed
`to detect additional analytes (for example to test a sample for
`the presence of a panel of narcotics). Multiple dipping steps
`such as are commonly used when multiple dipstick assays are
`separately performed, present not only possible loss of sen-
`sitivity of the assay (through reagent mixing or possible loss
`reagent solutions) but also an esthetic and hygienic problem
`for the analyst. Repetitive performance of assay procedures is
`also tedious, which increases the risk that assays will be
`performed improperly or the results misinterpreted.
`
`SUMMARY OF THE INVENTION
`
`The present invention provides an assay device, device for
`separating a fluid analyte sample for use in multiple assay
`procedures and methods for performing multiple analyte
`assays. In one embodiment of the assay device, the assay
`device is a dipstick having multiple analyte test strips, each of
`which includes a test zone and a control zone. The test strips
`are enclosed in a housing having an open side through which
`an end of each test strip protrudes to form a sample loading
`zone. A protective cap is provided to seal the protruding ends
`ofthe test strips from exposure while not in use. Each test strip
`is separated from the next within the housing by a raised
`spacer. The portion of the housing which overlies the test and
`control zones is transparent to permit visually observible
`results shown in each zone to be viewed.
`
`In cassette form, the assay device has the same structure
`described above, but the protruding test strips are inserted into
`a cap which has a sample port for application of sample to the
`test strips. The cap is retained on the assay device by a close
`fit over the device housing.
`Each test strip provides binders and assay reagents for
`detection of a different analyte in the sample fluid. In a par-
`ticularly preferred embodiment ofthe assay device, the hous-
`ing may be opened to permit substitution of different test
`strips to allow each device to be customized for detection of
`specific analytes of interest. Assay sample integrity determi-
`nants consisting of test strips which allow measurement of
`parameters such as specific gravity and pH may also be
`included in each device.
`
`The invention also provides a separator device for dividing
`a fluid assay sample into portions for use in multiple assays
`without need for contact between the assay operator and the
`fluid sample. This latter feature of the device increases opera-
`tor safety and avoids inadvertent contamination of the assay
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`2
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`sample. The separator device may be used to separate any
`fluid assay sample, but
`is especially useful
`in assaying
`samples for the presence of narcotics, where a positive result
`on first testing of the sample may necessarily be followed by
`additional testing of the sample to confirm the result and the
`identity of the detected narcotic. To this end, the separator
`device is adapted particularly well to use with the assay
`device of this invention.
`
`The assay device ofthe invention makes specimen analysis
`easierbecause an analyte sample need only to be applied once
`to the assay device for testing. In addition, the replaceable
`nature ofthe analyte test strips allows the analyst to customize
`the array of assays to the testing situation. Because the cus-
`tomization can be performed before adding the test sample
`(e.g., urine), fewer manipulations with the analyte sample are
`needed to obtain the desired information. In addition, use of
`the separator device permits further testing ofthe sample to be
`performed without risk of adultering the sample in a prelimi-
`nary assay performed according to the invention.
`The invention also provides a method for assaying one or
`more analytes of interest. The protruding ends of the device
`are dipped into a fluid analyte sample. Binding of an analyte
`present in the sample with one or more specific ligands causes
`formation of specific visual pattern in the test and control
`zones indicative ofthe test result. The as say results performed
`according to the invention may be read visually without use of
`separate measuring equipment. Thus, performance of assays
`according to the invention requires only that the user intro-
`duce the requisite amount oftest sample into the device ofthe
`invention,
`then observe any color changes which appear
`shortly thereafter in a detection zone of an analyte strip. The
`method of the invention is especially useful for screening
`fluid analyte samples (e.g., urine) for the presence or absence
`of drugs of abuse.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
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`FIG. 1 is an exploded view of a dipstick assay device ofthe
`invention.
`
`FIG. 2 is a top view of a dipstick assay device of the
`invention.
`
`FIG. 3A is a top view of the upper half sample port cap of
`a cassette assay device of the invention, and FIG. 3B is a top
`view of the lower half, base portion of the sample port cap,
`while FIG. 3C is a side, cut-away view of the intact cap with
`test strips in place therein.
`FIG. 4 is a top view ofthe separator device ofthe invention.
`FIG. 5 is a cross-sectional view of the separator device
`taken along line A-A at cut-away point B-B of FIG. 1.
`FIG. 6 is a lateral view of the separator device within a
`specimen collection cup.
`Like numerals refer to like elements in the drawings.
`
`DETAILED DESCRIPTION OF INVENTION
`
`A. Definitions
`
`For ease of understanding, the following definitions will
`apply throughout this description:
`1. The term “antigen” as used herein refers to any analyte
`which is capable of binding antibodies. Antigens may com-
`prise, without limitation, chemical compounds, polypeptides,
`carbohydrates, nucleic acids, lipids, and the like, including
`viral particles, viral subunits, bacterial and parasite surface
`antigens, and host proteins that may be diagnostic of the
`subject’s condition.
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`2. A “binder” refers to a ligand for the analyte as in the
`format of a sandwich assay, or a ligand for both the analyte
`and the tracer as in the format of a competitive assay. A binder
`can be chosen from a group of molecules or compounds
`capable of binding the analyte, such as an antigen to the
`antibody analyte, or an antibody to the antigen analyte.
`3. A “test zone” refers to an area in which a binder or the
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`analyte is attached, movably or immovably, to the test strip
`portion of an assay device.
`4. A “tracer” refers to a ligand for the analyte or the binder
`labeled with a detectable label, preferably a visually readable
`particulate label, such as colloidal gold, latex and liposomes
`including dye, carbon black, and the like.
`5. A “sample loading zone” refers to an area of a test strip
`on which a fluid analyte sample is applied for migration to the
`test zone.
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`6. A “test strip” ofthe invention consists of, collectively, all
`ofthe zone supporting membranes and any filters ofthe assay
`device.
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`7. A “fluid analyte sample” can be any fluid suspected of
`containing analyte of interest for which a particular assay is
`specific. Test sample may represent any body fluid, including
`urine, blood, sweat, lymph, intraperitoneal fluid, crude tissue
`extract or homogenate, derived from a fetus, neonate, juvenile
`or adult subject; a non-biological fluid such as water from
`some ecological niche, e.g., a river or a lake; or a solution used
`in a laboratory.
`8. A “label” is a molecule or compound which directly or
`indirectly mediates the formation of a signal (such as a color
`change) which is used in assay to indicate the presence,
`absence or concentration range of analyte of interest in a test
`sample. Labels may include enzymes, fluorescers, liposomes,
`erythrocyte ghosts, polymer microcapsules, color polymer
`particles (latex), and preferably includes sols of metal-con-
`taining compounds. A wide variety of patents and patent
`applications provide an extensive literature of different tech-
`niques for producing detectible signals in immunoassays. The
`following list ofUnited States patents is merely illustrative of
`the type of label which can find application in this invention:
`U.S. Pat. No. 3,646,346 discloses radioactive label; U.S. Pat.
`Nos. 3,654,090, 3,791,932, and 3,817,838 disclose enzyme
`labels; U.S. Pat. No. 3,996,345 discloses fluorescer-quencher
`labels; U.S. Pat. No. 4,062,733 discloses radioactive label;
`U.S. Pat. No. 4,067,959 discloses fluorescer or enzyme label;
`U.S. Pat. No. 4,104,099 discloses chemiluminescent label;
`and U.S. Pat. No. 4,160,645 discloses non-enzymatic catalyst
`label. U.S. Pat. No. 3,966,879 discloses an electrophoretic
`technique employing an antibody zone and U.S. Pat. No.
`4,120,945 discloses a radioimmune assay (RIA) where
`labeled analyte is initially bound to a solid support through
`antibody. U.S. Pat. No. 4,233,402 discloses enzyme pair
`labels; U.S. Pat. No. 4,720,450 discloses chemically induced
`fluorescent labels; and U.S. Pat. No. 4,287,300 discloses
`enzyme anionic charge labels.
`Labels can also be metal-containing sols; i.e., metal or
`metal compounds such as metal oxides, metal hydroxides,
`metal salts, metals or metal-containing compounds mixed
`with polymers or coated onto polymer nuclei. These metal
`labels may include dry forms of any of the above-named
`metal or metal compound sols, and preferably includes col-
`loidal gold in dry form.
`9. A “complex” means (depending on the context) any
`multimolecular complex formed by analyte and one or more
`ligands, or by labeled ligand and immobilized ligand. In a
`sandwich-type immunoassay, e.g., the following complexes
`occur: analyte/labeled ligand duplex first produced in the
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`assay (first complex) and analyte/labeled ligand/immobilized
`ligand triplex formed second in the assay (second complex).
`10. “Fluid communication” refers to structures which are
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`in contact with, but not necessarily aflixed to, one another.
`11. “Assay” refers to several different types of assay for-
`mats in which an analyte of interest can be detected using an
`assay test strip. For example, in a sandwich-type immunoas-
`say, analytes of interest in the analyte sample, when present,
`bind a labeled tracer movably incorporated in the test strip
`(consisting of a porous membrane) at the tracer zone to form
`a first complex. The tracer is a molecule which binds the
`analyte of interest and is conjugated to a label, preferably a
`metal label, and most preferably colloidal gold.
`A second immobilized ligand corresponding to the analyte
`of interest is coupled to the test strip at the test zone. First
`complex and unbound labeled ligand mix with the test sample
`and be carried along therewith by capillary action (wicking)
`through the test zone. Analyte sample passes through the test
`strip bringing the first complexes, if any, into contact with the
`unlabeled ligand immobilized in the test zone to form a sec-
`ond complex of labeled ligand-analyte-immobilized ligand.
`The first immobilized ligand is immobilized in the test zone
`by means known in the art, including covalent bonding or
`attachment to an insoluble protein-coated surface (see, e.g.,
`U.S. Pat. Nos. 4,200,690 and 5,075,078). When the second
`complex is formed, a visible color pattern appears in the test
`zone. Labeled ligand not bound to analyte in the test sample
`continue migration by wicking into the control zone to con-
`tact the ligand immobilized there. The labeled ligand can bind
`the immobilized ligand in the control zone to form a third
`complex, and thus be captured in the control zone.
`Within the scope ofthis invention, the labeled ligand form-
`ing the complex in the control zone may be the same as the
`tracer forming the first and second complexes, or it may be a
`different labeled ligand. The ligand immobilized in the con-
`trol zone should have specific aflinity for the labeled ligand
`intended to form the third complex. Formation of the third
`complex is indicated by a visible pattern in the control zone.
`Besides sandwich immunoassay method, other assay
`methods may be implemented in the devices of the invention.
`These methods may include competition and inhibition
`assays. In a competition assay, the analyte and tracer have
`similar affinity properties and compete for binding with
`immobilized ligand. Thus, in absence of analyte, the pattern
`(e.g., band) in the test zone is of maximum intensity. When
`present, the analyte binds to immobilized ligand to prevent
`the tracer from getting captured in the test zone. Thus, the
`intensity of the test band is reduced, depending on the con-
`centration of analyte in the test sample.
`In an inhibition assay, the analyte and immobilized ligand
`in the test zone each have affinity for the tracer. In the absence
`of analyte in the analyte sample, the tracer is captured by
`immobilized ligand, and a visible pattern forms in the test
`zone. When present, the analyte binds the tracer, thereby
`preventing it from binding to the immobilized ligand in the
`test zone. The resulting intensity of the test band is reduced
`depending on the concentration of analyte in the test sample.
`
`B. Dipstick Assay Device
`
`Turning to FIG. 1, a dipstick form of the assay device is
`shown in exploded view. The device consists of a housing
`100, which is defined by base 101 and cover 110. Base 101
`can be constructed of any sterilizable material, such as a
`nonporous plastic (e.g., the commercially available plastic
`“ABS” supplied by the Monsanto Company of St. Louis,
`Mo.). Base 101 having a closed end 104 and an open end 106,
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`slots 102A, 102B, 102C, 102D and 102E separated by rails
`103A, 103B, 103C and 103D for insertion oftest strips 105A,
`105B, 105C, 105D and 105E. A particular advantage of this
`embodiment of the assay device is its customizability in that
`test strips specific for different analytes of interest to the user
`may be inserted into base 101 and that the number of test
`strips employed may vary (e.g., base 101 may have any num-
`ber of slots from two upward to accomodate as many test
`strips as the user may desire).
`Referring to FIG. 2, when inserted into slots 102A, 102B,
`102C, 102D and 102E, the test strips extend out ofbase 101
`beyond open end 106. The length to which the test strips
`protrude from base 101 must be suflicient to allow the test
`strips to contact a fluid analyte sample, preferably by immer-
`sion, and most preferably without allowing the fluid to con-
`tact housing 100. The test strips are conventional in form;
`therefore, because those of ordinary skill in the art will be
`abundantly familiar with the design of such test strips, they
`will not be described in detail here. However, each test strip
`will have a test zone 112 for binding of analyte (to indicate a
`positive test result for the presence of analyte in the analyte
`sample) and a control zone 113 for binding of tracer (to
`indicate correct operation of the assay). Preferably, the test
`zones and control zones of each test strip lie in the same
`location on each test strip so each can be viewed in side-by-
`side fashion.
`
`Each test strip is typically constructed of a porous mem-
`brane which is substantially inert with respect to the analyte
`and must be porous or absorbent relative to the analyte sample
`to be tested, e.g., urine. The substance can be either bibulous
`matrices or nonbibulous matrices that are insoluble in, and
`maintain their structural integrity when exposed to aqueous
`solutions or physiological fluids. Bibulous matrices that can
`be useful for the devices of the present invention include but
`are not limited to, paper, sponge materials, cellulose, hydro-
`philic inorganic powders, wood, synthetic resin fleeces,
`woven and nonwoven fabrics and like materials. Nonlimiting
`examples of nonbibulous matrices include glass fiber, perme-
`able polymer films and preformed or microporous mem-
`branes. The absorbent material is preferably absorbent paper.
`The absorbent material can be affixed by a double sided
`adhesive (e.g., two sided adhesive tape) to a solid moisture
`impervious support. This support can be constructed from,
`for example, hydrophobic plastic, cellulose acetate, polyeth-
`ylene, terephthalate, polycarbonate, or polystyrene.
`The tracer is prepared according to the means known in the
`art. For purposes of producing a clearly visible reaction,
`labels of metal-containing sols are preferred, with labels of
`colloidal gold or selenium being most preferred. An example
`of a suitable product is colloidal gold available from Janssen
`Life Sciences Products. These colloidal metals produce dis-
`tinctive visual patterns without addition of further reagents;
`however, fluorescers (such as fluorescein) and enzymes (such
`as those identified in U.S. Pat. No. 4,275,149), may also be
`used.
`
`Selections and choices for test binders (e.g., immobilized
`antigens, antibodies and other test and control binders), as
`well as suitable means for their attachment to porous test strip
`membranes, are well-known to those of ordinary skill in the
`art and will not be stated in detail here. To maximize contact
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`of test sample with the tracer and all test binders, the area
`occupied by each reagent on the test strip preferably extends
`from one side of the membrane to the other.
`
`For further review concerning test strip construction,
`including selection and preparation of test reagents, the fol-
`lowing references provide a representative sample oftest strip
`designs known in the art: U.S. Pat. No. 5,384,264 (commonly
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`owned); U.S. Pat. No. 4,491,645; U.S. Pat. No. 4,943,522;
`U.S. Pat. No. 5,252,496; U.S. Pat. No. 5,714,389 and U.S.
`Pat. No. 5,602,040, the disclosures ofwhich are incorporated
`for purposes of reference.
`Test strips 105A, 105B, 105C, 105D and 105E may be
`secured within slots 102A, 102B, 102C, 102D and 102E by
`adhesion to the floor of each slot; however, the placement of
`cover 110 onto base 101 is suflicient to retain the test strips
`within the base slots. To this end, cover 110 is conveniently
`constructed of an opaque tape having at least one transparent
`window 111 formed therein for viewing of test results along
`test zone 112 and control zone 113. To secure cover 110 onto
`base 101, as well as to secure test strips 105A, 105B, 105C,
`105D and 105E within slots 102A, 102B, 102C, 102D and
`102E, cover 110 is pressed into place to form an adhesive
`attachment between cover 110 and the upper edges of rails
`103A, 103B, 103C, and 103D. To provide additional surface
`area for adhesion ofcover 110 to base 101, bar 107 separates
`closed endwall 104 ofbase 101 from rails 103A,103B,103C,
`and 103D.
`Conveniently, cover 110 is also provided with transparent
`windows 115A, 115B, 115C, 115D and 115E through which
`labels on test strips 102A,102B,102C, 102D and 102E can be
`viewed. The labels (not shown) may be printed with informa-
`tion of use in performing the assay, such as the identity of
`analyte detectible with each test strip.
`In certain instances, it may be desirable to store the assay
`device after test results are obtained for later viewing. To that
`end, a five-sided cap 120 is provided for insertion over open
`end 106 of base 101 (with cover 110 in place) to protect the
`protruding ends of test strips 102A, 102B, 102C, 102D and
`102E from contact with other materials, from dessication and
`from contact with the assay operator. Cap 120 is easily
`secured onto the assay device by a close fit, such as a friction
`fit or snap-fit.
`
`C. Cassette Assay Device
`
`In some instances (e.g., where the analyte sample is
`believed to contain pathogenic organisms) it is desirable to
`protect the assay operator from contact with analyte sample
`after its application to an assay device. To this end, the dip-
`stick assay device may be conveniently modified for use in
`closed cassette form.
`
`More specifically, cap 220 (FIGS. 3A and 3B) is adapted to
`convert the dipstick assay device into a cassette. Cap 220 is
`similar in design to cap 120 (FIGS. 1 and 2), except that
`sample application slot 221 is formed therein to permit ana-
`lyte sample to be applied to test strips 202A, 202B, 202C,
`202D and 202E dropwise; e.g., by pipetting the sample
`through slot 221 (in FIG. 3C, only strip 202A is visible from
`the side view and the device housing is not shown). To avoid
`sample overflow, a reservoir 222 may be provided in the inner
`floor 223 of cap 220 by, for example, providing raised bar 226
`on floor 223 (in FIGS. 3A and 3B, floor 223 is shown as if split
`from roof 225 of the cap only for the purpose of permitting
`reservoir 222 to be viewed in the drawing). A downwardly
`protruding bar 224 is provided from the inner surface of roof
`225 of cap 220 to depress the test strips into reservoir 222 so
`each test strip has equal access to the analyte sample. After
`performance of the assay, cap 220 remains in place on the
`assay device to protect the protruding ends of the test strips
`from contact with other materials, from dessication and from
`contact with the assay operator.
`
`D. Separator Device for Division of Analyte Sample
`
`If a positive result is obtained from use of the assay device
`ofthe invention, it is usually necessary to further characterize
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`US 8,623,291 B2
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`the detected compound to better enable its identification; e.g.,
`by mass spectrometry. However, it is rarely practical to ask
`that more than one assay sample be obtained from a subject.
`As such, any assay sample which is obtained must be divided
`into portions of suflicient volume for repeated testing, for
`example by pouring the original sample into separate speci-
`men containers (at the risk of operator contamination and
`sample loss). Even where the sample is only to be assayed
`once, the tendency of subjects to provide abundant urine
`samples poses a different problem in that too much sample
`can saturate a test strip and overwhelm the assay reagents.
`Again, division of the sample is required.
`The separator device of the invention provides simple
`means for dividing a sample while protecting the sample from
`contamination and the operator from the sample. To these
`ends, the separator device consists of a ring which is just
`smaller in diameter than the inner diameter ofthe open end of
`a specimen collection cup so, when pressed inside ofthe open
`end of the cup, the ring will remain seated there. A collection
`chamber (for example, a “V” shaped well) extends across the
`ring and is attached thereto so the ends of the collection
`chamber are closed by the inner walls of the ring.
`In use, an assay fluid is placed within the specimen collec-
`tion cup to a level below the point where the separator device
`will be seated. The assay operator presses the separator device
`into place and seals the specimen collection cup with a cap.
`The operator inverts the specimen collection cup several
`times so fluid pours into the collection chamber of the sepa-
`rator device. The balance ofthe fluid assay remains below the
`level of the separator device and is therefore protected from
`contact with reagents or other material placed therein. A test
`strip (such as the assay device of the invention) is placed into
`contact with the portion of the assay sample contained within
`the collection chamber of the separator device; e.g., by dip-
`ping an end of the test strip into the collection chamber. After
`the assay sample is loaded from the collection chamber onto
`the test strip, the latter is removed and the separator device is
`carefully lifted from the specimen collection cup for disposal.
`Use of the separator device provides the assay operator
`with a volume of assay sample fluid which is sufficiently
`limited to avoid saturation of the test strip. For example,
`where the assay device utilized is the device of this invention,
`the collection chamber is of a depth and length sufficiently
`limited so the maximum fluid level achievable in the collec-
`
`tion chamber is lower than the level of the assay device
`housing. The uncontaminated balance of the assay sample
`still in the specimen collection cup is available for further
`testing; e.g., for mass spectrometry to determine the identity
`of any compounds detected in the initial assay of the portion
`ofthe sample separated in the separator device. Conveniently,
`the separator device may be provided in the form of a kit,
`including the separator device, a sterilized specimen collec-
`tion cup with cap and forceps for removal of the separator
`device from the cup after performance ofthe assay. Such a kit
`may also be provided with the assay device of the invention.
`An example of a separator device is shown in FIGS. 4
`through 6. Although the separator device shown is in the
`shape of a ring (to correspond to the common cup-like shape
`ofurine collection cups), those of ordinary skill in the art will
`recognize that the separator device may be of any shape
`which conforms to a specimen collection container having at
`least one open end into which the separator device may be
`seated.
`
`Referring to FIG. 4, a top view of separator device 400 is
`provided. Ring 401 has an OD of slightly less than the ID of
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`the specimen collection cup into which the separator device is
`to be placed. Collection chamber 402 spans ring 401 and is
`defined by walls 403 and 404.
`Looking through separator device 400 along line A-A from
`cut-away point B-B (FIG. 5), it is seen that walls 403 and 404
`meet at point 405 to form aV-shaped well. Those of ordinary
`skill in the art will recognize that collection chamber 402 may
`take the form of a half-circular, squared or other shaped well,
`but a V-shape is a convenient well form to manufacture.
`Collection chamber 402 is closed at both ends of the well by
`inner surface 406 of ring 401. Also, it will be appreciated that
`separator device 400 may be provided with more than one
`collection chamber.
`
`FIG. 6 shows separator device 400 in place within speci-
`men collection cup 410. It can be seen from FIG. 6 that the
`height of ring 401 is restricted so neither it nor collection
`chamber 402 extend above the level ofthe open mouth 411 of
`cup 410 (to avoid interfering with closure of cup 410 by its
`cap [not shown]). Assay sample fluid 412 remains below
`separator device 400 in cup 410.
`Separator device 400 may be constructed of any steriliz-
`able material which is acceptable for use with fluid assay
`samples, the identity of which will be known to those of
`ordinary skill in the art (e.g., plastics such as polycarbonate
`and glass). Preferably, the material will be non-porous and
`hydrophobic.
`
`E. Methods for Use of the Assay Devices
`
`The method of the invention may be used to detect any
`analyte present in fluid sample. The invention is especially
`useful for detection of monoepitopic and polyepitopic anti-
`gens and antibodies associated with pathologies, as well as
`physiological compounds and drugs.
`The assay devices of the invention are particularly well
`suited for use in drug screening assays and for diagnostic
`testing of organisms. In the former respect, a five drug panel
`of assay tests is recommended by the National Institute on
`Drug Abuse (NIDA), which includes tests for tetrahydrocan-
`nabinol and other marijuana metabolites, cocaine metabo-
`lites, opiate metabolites, phencyclidine (PCP, Angel Dust),
`and amphetamines. For a more extensive substance abuse
`testing panel, the choice of analytes tested can include mari-
`juana metabolites; tetrahydrocarmabinol and other marijuana
`metabolites, cocaine metabolites, opiate metabolites, phen-
`cyclidine (PCP, Angel Dust), amphetamines, barbiturates,
`benzodiazepines, methaqualone, and propoxyphene. The
`analyte test strips for drug tests preferably have the sensitivity
`equal to the cutoffs recommended by Substance Abuse Men-
`tal Health Service Administration (SAMSHA) and NIDA,
`which most employers use. Binders and reagents for use in
`constructing test strips for use in detecting drugs of abuse are
`well-known in the art and will not be described in detail here;
`however,
`representative sources of such materials are
`described in the Examples below.
`Subjects undergoing drug tests are often creative in their
`attempts to adulterate the analyte samples to evade detection
`of drugs of abuse likely to be present in the sample. To
`minimize the effects of such evasion efforts on results obtain-
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`able with the assay devices ofthe invention, test strips may be
`provided in the devices which indicate the integrity and con-
`dition of the analyte sample. For example, test strips may be
`provided to simultaneously assay the analyte sample for for
`pH, osmolality (the total concentration of solutes in urine,
`expressed as mOsm/kg and measured as a function of fluid
`specific gravity), or the presence of albumin.
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`In test strips for pH, the strip is impregnated with various
`dyes that respond with different color changes to a pH in the
`range of 5 to 9. Depending on the acid-base status, urinary pH
`may range from as low as 4.5 to as high as 8.0. Although this
`test
`is done routinely,
`it neither identifies nor excludes
`patients with urinary system disease. The test can, however,
`indicate that the condition of the urine sample has deterio-
`rated.
`
`To test the specific gravity (which is directly proportional
`to urine osmolality) of an analyte test fluid, analyte test strips
`are available that measure specific gravity in approximations.
`For example, U.S. Pat. No. 4,318,709, to Falb et al., issued
`Mar. 9, 1982, provides a test means for determining the ionic
`strength or specific gravity of an aque