Method of solid phase immunoassay incorporating a luminescent label

• US 4,652,533 A
• Filed: 04/28/1983
• Issued: 03/24/1987
• Est. Priority Date: 04/28/1983
• Status: Expired due to Term

• Current Assignee: Abbott Laboratories
• Original Assignee: Pandex Laboratories, Inc.
• Inventors: Jolley, Michael E.
• Primary Examiner(s): Warren, Charles F.
• Assistant Examiner(s): Moskowitz, M.
• Application Number:
  US06/489,519
• Time in Patent Office: 1,426 Days
• Field of Search: 436/518-535, 436/544, 436/536, 436/538-540, 436/546, 436/807, 436/809, 436/824, 436/165, 436/172, 435/4, 435/7, 435/5, 435/8, 422/55-61, 422/52
• US Class Current: 435/5
• CPC Class Codes: G01N 33/54313 the carrier being characterised by its particulate form
• CPC Class Codes: G01N 33/544 the carrier being organic
• CPC Class Codes: G01N 33/573 for enzymes or isoenzymes
• CPC Class Codes: G01N 33/585 with a particulate label, e.g. coloured latex
• CPC Class Codes: G01N 33/586 Liposomes, microcapsules or cells
• CPC Class Codes: Y10S 435/968 High energy substrates, e.g. fluorescent, chemiluminescent, radioactive
• CPC Class Codes: Y10S 436/807 Apparatus included in process claim, e.g. physical support structures
• CPC Class Codes: Y10S 436/809 Multifield plates or multicontainer arrays

Abstract

A method is provided for solid phase immunoassay for quantitation of antigen, hapten or antibody analyte in liquid sample and alternatively for quantitation of analyte occuring on or attached to cells or other particulate material in a liquid sample. The solid phase is suspended for at least the initial reactions and is subsequently concentrated by microfiltration to a volume substantially less than the sample volume. Luminescence of substantially the entire label on the concentrated solid phase is measured.

Claims

1. A luminescence solid phase immunoassay comprising:

placing within a microfiltration well (1) a sample suspected of containing an analyte, (2) a plurality of water insoluble particulates selected from the group consisting of particles having a size of not more than about 10 microns and biological cells, said particulates having attached thereto an immunoreactant specific for the analyte, and (3) a luminescent labeled material selected from the group consisting of material which selectively binds with said immunoreactant and material which selectively binds with said analyte, such that a fluid mixture is formed containing the sample, the luminescent labeled material and the particulates and such that said particulates are dispersed within said fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said immunoreactant and reaction according to said binding of said luminescent labeled material;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescence.

15. The method of claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14 whereinthe water insoluble particulates are particules having a size not more than about 10 microns.

16. The method of claim 15 wherein the particles having a size not more than 10 microns.

17. The method of claim 15 wherein the particles are selected from the group consisting of bacteria cell fragments, mammalian cell fragments and polymeric beads.

18. The method of claim 17 wherein the particles are polymeric beads.

19. The method of claim 18 wherein the polymeric beads comprise polystyrene latex.

20. The method of claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14 wherein the water insoluble particulates are substantially transparent to the luminescence of the luminescent label.

2. A luminescence solid phase immunoassay comprising:

placing within a microfiltration well (1) a sample suspected of containing an analyte and (2) a plurality of water insoluble particulates selected from the group consisting of particles having a size of not more than about 10 microns and biological cells, said particulates having attached thereto an immunoreactant specific for the analyte, such that a fluid mixture is formed containing the sample and the particulates and such that said particulates are dispersed within said fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said immunoreactant;

placing within said microfiltration well (3) a luminescent labeled material selected from the group consisting of material which selectively binds with said immunoreactant and material which selectively binds with said analyte, such that a second fluid mixture is formed containing the luminescent labeled material and the particulates and such that said particulates are dispersed within said second fluid mixture;

incubating said second fluid mixture for a time and under conditions sufficient to permit reaction according to said binding of said luminescent labeled material;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescence.

3. A luminescence solid phase immunoassay comprising:

placing within a microfiltration well (1) a sample suspected of containing an analyte and (2) a plurality of water insoluble particulates selected from the group consisting of particles having a size of not more than about 10 microns and biological cells, said particulates having attached thereto an immunoreactant specific for the analyte, such that a fluid mixture is formed containing the sample and the particulates and such that said particulates are dispersed within said fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said immunoreactant;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone;

placing within said microfiltration well (3) a luminescent labeled material selected from the group consisting of material which selectively binds with said immunoreactant and material which selectively binds with said analyte, such that a second fluid mixture is formed containing the luminescent labeled material and the particulates;

incubating said second fluid mixture for a time and under conditions sufficient to permit reaction according to said binding of said luminescent labeled material;

filtering said second fluid mixture in a manner such that the layer of substantially all the particulates remains within or such a layer is reformed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescence.

4. A luminescence solid phase immunoassay comprising:

placing within a microfiltration well (1) a sample suspected of containing an analyte and (2) a luminescent labeled material which selectively binds with said analyte, such that a fluid mixture is formed containing the sample and the luminescent labeled material;

incubating said fluid mixture for a time and under conditions sufficient to permit reaction according to said binding of said luminescent labeled material;

placing within said microfiltration well (3) a plurality of water insoluble particulates selected from the group consisting of particles having a size of not more than about 10 microns and biological cells, said particulates having attached thereto an immunoreactant specific for the analyte, such that a second fluid mixture is formed containing the particulates and such that said particulates are dispersed within said fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the second fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said immunoreactant;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescence.

5. A luminescence solid phase immunoassay comprising:

placing within a microfiltration well (1) a plurality of water insoluble particulates selected from the group consisting of particles having a size of not more than about 10 microns and biological cells, said particulates having attached thereto an immunoreactant, and (2) a luminescent labeled material which selectively binds with said immunoreactant, such that a fluid mixture is formed containing the luminescent labeled material and the particulates and such that said particulates are dispersed within said fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said fluid mixture for a time and under conditions sufficient to permit reaction according to said binding of said luminescent labeled material;

placing within said microfiltration well (3) a sample suspected of containing an analyte specific for said immunoreactant, such that a second fluid mixture is formed containing the sample and the particulates and such that said particulates are dispersed within said second fluid mixture;

incubating said second fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said analyte;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescence.

6. A luminescence solid phase immunoassay comprising:

placing within a microfiltration well (1) a plurality of water insoluble particulates selected from the group consisting of particles having a size of not more than about 10 microns and biological cells, said particulates having attached thereto an immunoreactant, and (2) a luminescent labeled material which selectively binds with said immunoreactant, such that a fluid mixture is formed containing the luminescent labeled material and the particulates and such that said particulates are dispersed within said fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said fluid mixture for a time and under conditions sufficient to permit reaction according to said binding of said luminescent labeled material;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone;

placing within said microfiltration well (3) a sample suspected of containing an analyte specific for said immunoreactant, such that a second fluid mixture is formed containing the sample and the particulates;

incubating said second fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said analyte;

filtering said second fluid mixture in a manner such that the layer of substantially all the particulates remains within or such a layer is reformed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescense.

7. A luminescence solid phase immunoassay comprising:

placing within a microfiltration well (1) a sample suspected of containing an analyte, (2) a plurality of water insoluble particulates selected from the group consisting of particles having a size of not more than about 10 microns and biological cells, said particulates having attached thereto a first immunoreactant, (3) a luminescent labeled material, and (4) a second immunoreactant that is specific for said analyte and said first immunoreactant and that selectively binds with said luminescent labeled material, such that a fluid mixture is formed containing the sample, the luminescent labeled material, the second immunoreactant and the particulates and such that said particulates are dispersed within said fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said fluid mixture for a time and under conditions sufficient to permit immunoreactions accorping to said specificity of said second immunoreactant and reaction according to said binding of said second immunoreactant;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescense.

8. A luminescence solid phase immunoassay comprising:

placing within a microfiltration well (1) a sample suspected of containing an analyte, (2) a luminescent labeled material and (3) a first immunoreactant that is specific for said analyte and that selectively binds with said luminescent labeled material, such that a fluid mixture is formed containing the sample, the luminescent labeled material and the first immunoreactant;

incubating said fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said first immunoreactant and reaction according to said binding of said first immunoreactant;

placing within said microfiltration well (4) a plurality of water insoluble particulates selected from the group consisting of particles having a size of not more than about 10 microns and biological cells, said particulates having attached thereto a second immunoreactant specific for said first immunoreactant, such that a second fluid mixture is formed containing the particulates and such that said particulates are dispersed within said second fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the second fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said second fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said second immunoreactant;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescense.

9. A luminescence solid phase immunoassay comprising:

placing within a microfiltration well (1) a sample suspected of containing an analyte and (2) a first immunoreactant that is specific for said analyte, such that a fluid mixture forms containing the sample and first immunoreactant;

incubating said fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said immunoreactant;

placing within said microfiltration well (3) a luminescent labeled material which binds with said first immunoreactant, such that a second fluid mixture is formed;

incubating said second fluid mixture for a time and under conditions sufficient to permit reaction according to said binding of said luminescent labeled material;

placing within said microfiltration well (4) a plurality of water insoluble particulates selected from the group consisting of particles having a size of not more than about 10 microns and biological cells, said particulates having attached thereto a second immunoreactant specific for said first immunoreactant, such that a third fluid mixture is formed containing the particulates and such that said particulates are dispersed within said third fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the third fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said third fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said second immunoreactant;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescense.

10. A luminescence solid phase immunoassay comprising:

placing within a microfiltration well (1) a first immunoreactant and (2) a luminescent labeled material which binds with said first immunoreactant, such that a fluid mixture is formed containing the first immunoreactant and the luminescent labeled material;

incubating said fluid mixture for a time and under conditions sufficient to permit reaction according to said binding of said luminescent labeled material;

placing within said microfiltration well (3) a sample suspected of containing an analyte specific for said first immunoreactant, such that a second fluid mixture is formed containing the sample;

incubating said second fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said immunoreactant analyte;

placing within said microfiltration well (4) a plurality of water insoluble particulates selected from the group consisting of particles having a size of not more than about 10 microns and biological cells, said particulates having attached thereto a second immunoreactant specific for said first immunoreactant, such that a third fluid mixture is formed containing the particulates and such that said particulates are dispersed within said third fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the third fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said third fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said second immunoreactant;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescense.

11. A luminescence solid phase immunoassay comprising:

placing within a microfiltration well a sample suspected of containing an analyte, (2) a plurality of water insoluble particulates selected from the group consisting of particles having a size of not more than about 10 microns and biological cells, said particulates having attached thereto an immunoreactant, and (3) a luminescent labeled material specific for said analyte and specific for said immunoreactant, such that a fluid mixture is formed containing the sample, the luminescent labeled material and the particulates and such that said particulates are dispersed within said fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificities of said luminescent labeled material;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescense.

12. A luminescence solid phase immunoassay comprising:

placing within a microfiltration well (1) a luminescent labeled material and (2) a plurality of water insoluble particulates selected from the group consisting of particles having a size of not more than about 10 microns and biological cells, said particulates having attached thereto an immunoreactant specific for the luminescent labeled material, such that a fluid mixture is formed containing the luminescent labeled material and the particulates and such that said particulates are dispersed within said fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said immunoreactant;

placing within said microfiltration well (3) a sample suspected of containing an analyte which is specific for said luminescent labeled material, such that a second fluid mixture is formed containing the sample and the particulates and such that the particulates are dispersed within said second fluid mixture;

incubating said second fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said analyte;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescense.

13. A luminescence solid phase immunoassay comprising:

placing within a microfiltration well (1) a luminescent labeled material and (2) a plurality of water insoluble particulates selected from the group consisting of particles having a size of not more than about 10 microns and biological cells, and particulates having attached thereto an immunoreactant specific for the luminescent labeled material, such that a fluid mixture is formed containing the luminescent label material and the particulates and such that said particulates are dispersed within said fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said immunoreactant;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone;

placing within said microfiltration well (3) a sample suspected of containing analyte which is specific for said luminescent labeled material, such that a second fluid mixture is formed containing the sample and the particulates;

incubating said second fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said analyte;

filtering said second fluid mixture in a manner such that the layer of substantially all the particulates remains within or such a layer is reformed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescense.

14. A luminescence solid phase immunoassay comprising:

placing within a microfiltration well (1) a sample suspected of containing an analyte and (2) a luminescent labeled material which is specific for said analyte, such that a fluid mixture is formed containing the sample and the luminescent labeled material;

incubating said fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said luminescent labeled material;

placing within said microfiltration well (3) a plurality of water insoluble particulates selected from the group consisting of particles having a size of not more than about 10 microns and biological cells, said particulates having attached thereto an immunoreactant specific for the luminescent labeled material, such that a second fluid mixture is formed containing the particulates and such that said particulates are dispersed within said fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the second fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said second fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said immunoreactant;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescense.

21. A luminescence solid phase immunoassay comprising:

placing within a microfiltration well (1) a sample suspected of containing analyte occuring on or attached to the surface of a plurality of particulates selected from the group consisting of biological cells and microparticulate material having a size not more than that of biological cells and (2) a luminescent labeled material specific for said analyte, such that a fluid mixture is formed containing the sample and the luminescent labeled material and such that said particulates are dispersed within said fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said luminescent labeled material;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescense.

25. The method of claims 21, 22, 23 or 24 wherein the biological cells are selected from the group consisting of bacteria cells and mammalian cells.

26. The method of claims 21, 22, 23 or 24 wherein the microparticulate material is selected from the group consisting of polymeric beads having a size of not more than about 10 microns and biological cell fragments.

27. The method of claim 26 wherein the polymeric beads have a size of not more than 10 microns.

28. The method of claims 21, 22, 23 or 24 wherein the analyte is selected from the group consisting of a biological cell surface antigen, a viral surface antigen, a bacterial surface antigen, a soluble protein, a soluble hapten and a soluble virus.

22. A luminescence solid phase immunoassay comprising:

placing within a microfiltration well (1) a sample suspected of containing an analyte occurring on or attached to the surface of a plurality of particulates selected from the group consisting of biological cells and microparticulate material having a size not more than that of biological cells, (2) an immunoreactant specific for said analyte, and (3) a luminescent labeled material which binds with said immunoreactant, such that a fluid mixture is formed containing the sample, the particulates and the luminescent labeled material and such that said particulates are dispersed within said fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said immunoreactant and reaction according to said binding of said luminescent labeled material;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescense.

23. A luminescense solid phase immunoassay comprising:

placing within a microfiltration well (1) a sample suspected of containing analyte occurring on or attached to the surface of a plurality of particulates selected from the group consisting of biological cells and microparticulate material having a size not more than that of biological cells and (2) an immunoreactant specific for said analyte, such that a fluid mixture is formed containing the sample and the particulates and such that said particulates are dispersed within said fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said immunoreactant;

placing within said microfiltration well (3) a luminescent labeled material which binds with said immunoreactant, such that a second fluid mixture is formed containing said luminescent labeled material and said particulates and such that said particulates are dispersed within said fluid mixture;

incubating said second fluid mixture for a time and under conditions sufficient to permit reaction according to said binding of said luminescent labeled material;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescence.

24. A luminescence solid phase immunoassay comprising:

placing within a microfiltration well (1) a sample suspected of containing analyte occurring on or attached to the surface of a plurality of particulates selected from the group consisting of biological cells and microparticulate material having a size not more than that of biological cells and (2) an immunoreactant specific for said analyte, such that a fluid mixture is formed containing the sample and the particulates and such that said particulates are dispersed within said fluid mixture, resulting in a high ratio of said particulates'"'"' surface area to the fluid mixture'"'"'s volume, said well containing a filter membrane, the area of the filter membrane being selected such that a sizable concentration of the particulates results upon filtration and such that a discrete measuring zone results;

incubating said fluid mixture for a time and under conditions sufficient to permit immunoreaction according to said specificity of said immunoreactant;

concentrating the dispersed particulates by filtration in a manner such that a layer of substantially all the particulates is formed within the discrete measuring zone;

placing within said microfiltration well (3) a luminescent labeled material which binds with said immunoreactant, such that a second fluid mixture is formed containing said luminescent labeled material and said particulates and such that said particulates are dispersed within said fluid mixture;

incubating said second fluid mixture for a time and under conditions sufficient to permit reaction according to said binding of said luminescent labeled material;

filtering said second fluid mixture in a manner such that the layer of substantially all the particulates remains within or such a layer is reformed within the discrete measuring zone; and

measuring the zone which contains the layer of concentrated particulates for luminescense.