Diagnostic device

[54] DIAGNOSTIC DEVICE

[75] Inventor: Willftied Schramm, Ann Arbor, Mich.

[73] Assignee: BioQuant, Inc., Ann Arbor, Mich. [21] Appl. No.: 225,194 [22] Filed: Jul. 28,1988

[51] Int. CI.5 G01N 30/00

[52] U.S. CI. 422/82.05; 422/100;

422/102; 422/65; 422/82.08; 436/8

[58] Field of Search 422/68, 100, 102, 104,

422/64, 65, 73; 436/8, 14, 15, 16

[56] References Cited

U.S. PATENT DOCUMENTS

4,058,370 11/1977 Souvaniemi 422/100

4,265,855 5/1981 Mandle et al 422/65

4,345,843 8/1982 Berglund et al 422/64

4,383,041 5/1983 Kutsusawa et al 422/65

4,554,839 11/1985 Hewett et al 422/65

4,681,742 7/1987 Johnson et al 422/65

Primary Examiner—Barry S. Richman

Assistant Examiner—Gregory R. Muir

Attorney, Agent, or Firm—Reising, Ethington, Barnard,

Perry & Milton

[57] ABSTRACT

A diagnostic device (10) includes a plurality of standard solutions for being dispensed into a row of wells (20), the standard solutions contained within a predetermined number of standard tubes which are spaced a predetermined distance apart equal to the distance between the plurality of wells (20) whereby a single pipettor (28) can transfer the standards from the entire row of standard tubes (26) to a single row of wells (20) in a single transfer step. The invention further provides a mixing mechanism for agitating the entirety of a microtiter plate seated thereover.

10 Claims, 2 Drawing Sheets

DIAGNOSTIC DEVICE

TECHNICAL FIELD

10

The present invention relates to a diagnostic device for assaying unknown constituent concentrations of a sample. More specifically, the present invention relates to a diagnostic kit used for immunoassay determinations of constituents such as hormones in a blood sample.

BACKGROUND ART

It is desirable to make efficient and qualitatively accurate determinations of microscopic amounts of constituents of samples, such as the determination of analytes including hormones, enzymes, metabolites, and drugs in 15 a sample of blood or other fluid. Immunoassay techniques have been used for such determinations.

Immunoassay (IA) is the generic term for systems of quantitative in vitro measurement based on the principal of saturation analysis, displacement analysis, or 20 competitive analyte binding. Since such techniques are extremely sensitive and very specific. IA techniques are used for the determination of physiologically, pharmocologically or forensically important analytes in biological fluids. 25

One of the techniques in IA is derived from the observation that unlabeled analyte displaces labeled analyte from an antibody that can bind the analyte. With an antibody concentration and the labeled analyte held constant, the binding of the label is quantitatively re- 30 lated to the amount of unlabeled analyte that is added. Thus, known analyte standards can be used initially to prepare a plot of the fraction of bound radioactive analyte against the concentration of added non-labeled analyte. 35

In operation, the method of heterogeneous immunoassays requires the separation of a labeled analyte of interest into bound and unbound fractions after its interaction with an antibody in the presence of an unknown quantity of unlabeled analyte. Homogeneous assays that 40 do not require a separation step are becoming increasingly popular.

Various devices are used in IA techniques. Occasionally, a microtiter plate is used, the microtiter plate being a plastic plate including a plurality of rows of wells for 45 containing the sample solutions. For example, an antibody can be bound to the walls of the wells. In radioimmunoassays (RIA), a derivative of the analyte which is radioactively labeled is used as signal generator for quantitative measurements of analyte. A sample or stan- 50 dard and radiolabeled analyte (tracer) are added to the wells The constituents of the wells are agitated during incubation and the liquid of the wells is removed. The wells are then separated and placed in a radioactivity counter to determine radioactive binding. Alterna- 55 tively, the analyte can be labeled with non-radioactive substances including enzymes and substances emitting fluorescence or luminescence. In addition, the label can be on a second binding substance that binds to the analyte that is already bound to the wall of the well. 60

Several problems have been uncovered utilizing the" aforementioned technique. Standards of the substance to be measured are prepared prior to assaying samples of unknown substance concentration from a stock solution of substance by serial dilutions. These dilutions are 65 then distributed to the designated wells or other containers which are then subjected to the assay procedure. From an obtained physical measurement (e.g. radioac

tivity), a standard curve is eventually constructed which represents the mathematical or graphical function (standard curve of the concentration of the substance in the standards, that being the known parameter) against the physical measurements of the unknown samples. The standard curve is then used to extrapolate from a physical measurement in a sample of unknown substance concentrations to the concentration predicted by the standard curve.

The disadvantage of this prior art technique involves the preparation of serial dilutions for the standards prior to assaying. This is inefficient because it is time consuming and can introduce inaccuracies by the operator. Each serial dilution allows for a first inaccuracy to be developed and each following serial dilution perpetuates and sometimes accentuates the inaccuracy. Therefore, there are prior art techniques utilizing predispensed standards. However, these standards are distributed such that each standard solution needs to be delivered to the assay well separately with a single pipettor.

A second concern is an efficient means for mixing the contents of each of the wells during the incubation step of the procedure. Care must be taken to not spill the contents of each well yet sufficient agitation must be made in order to properly mix the contents of each well.

Another concern during the processing of the samples of the microtiter plates is that some manufacturers manufacture trays comprising unitary rows of wells interconnected together, each row being connected at its end to a surrounding base of the plate. Once several rows are removed from the plate, it is possible to confuse the order of the rows and thereby lose the identity of tested samples.

The present invention provides an efficient means for providing for transfer a plurality of known concentration standards so that the standards can be transferred in a single step. The present invention further provides an effective and efficient means for agitating the wells containing the standards and samples. The present invention further provides a means of identifying the proper location of a row of wells which has been displaced from the microtiter plate to avoid loss of identity of the row. Finally, the present invention provides a single kit within a single housing incorporating the aforementioned inventions into a unitary kit providing all of the means necessary to conduct an IA incubation procedure.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a diagnostic device for assaying unknown constituent concentrations of a sample, the device including the combination of housing means for containing the device and tube means disposed within the housing means. The tube means includes a plurality of rows of wells for receiving and containing a sample including the constituent to be assayed. Each row includes a predetermined number of wells or tubes. Standard means is disposed within the housing means and contains a plurality of standard solutions for being dispensed into a row of the wells or tubes. The standard means includes the predetermined number of standard tubes, each of the tubes containing a known concentration of the constituent and each of the tubes being spaced the predetermined distance apart equal to the spacing of the wells in each of the rows whereby a single pipettor can transfer the standard from the entire row of standard tubes to a