Assays and devices therefor

• US 5,182,216 A
• Filed: 11/22/1988
• Issued: 01/26/1993
• Est. Priority Date: 01/22/1987
• Status: Expired due to Fees

• Current Assignee: Unilever Patent Holdings BV (Unilever PLC)
• Original Assignee: Unilever Patent Holdings BV (Unilever PLC)
• Inventors: Clayton, Richard A., Porter, Philip
• Primary Examiner(s): Rosen, Sam
• Application Number:
  US07/250,629
• Time in Patent Office: 1,526 Days
• Field of Search: 436/518, 436/501, 436/528, 436/535, 436/536, 436/169, 436/807, 436/808, 436/810, 436/817, 436/818, 435/7, 435/810, 422/55, 422/57, 422/58, 422/60, 422/61
• US Class Current: 436/518
• CPC Class Codes: G01N 33/54366 Apparatus specially adapted for solid-phase testing
• CPC Class Codes: G01N 33/76 Human chorionic gonadotropin including luteinising hormone, follicle stimulating hormone, thyroid stimulating hormone or their receptors
• CPC Class Codes: Y10S 436/807 Apparatus included in process claim, e.g. physical support structures
• CPC Class Codes: Y10S 436/81 Tube, bottle, or dipstick
• CPC Class Codes: Y10S 436/817 Steroids or hormones
• CPC Class Codes: Y10S 436/818 Human chorionic gonadotropin

Abstract

In a simultaneous marking specific binding assay for an analyte is a liquid sample, such as urine during pregnancy or fertile period test, wherein the liquid sample is simultaneously incubated with a first specific binding reagent immobilized on a solid phase carrier surface and with a second specific binding reagent dissolved or dispersed in the liquid sample and which bears a label by means of which the result of the assay can be determined, the improvement that prior to the incubation the second specific binding reagent is contained within a layer (2a) of readily soluble or dispersible solid material superimposed on the solid phase carrier surface (2a) on which the first specific binding reagent is immobilized. When the solid material dissolves or disperses in the sample liquid, the labelled reagent is released into the sample liquid at the same time as the immobilized reagent is exposed to the sample, and the close proximity of the two reagents overcomes the "hook effect" when the analyte is in high concentration in the sample. (FIG. 2C).

Claims

1. In a specific binding assay for an analyte in a liquid sample involving the steps of simultaneously incubating the liquid sample with a first specific antibody binding reagent immobilised on a solid phase carrier surface and with a second specific antibody binding reagent dissolved or dispersed in the liquid sample and which bears a label by means of which the result of the assay can be determined, permitting a sandwich reaction to occur during incubation between the antibody binding reagents and the analyte and then detecting the amount of reaction which has occurred, the improvement which involves using, as the second binding reagent, an antibody which is contained within a layer of solid material which is applied as a coating superimposed over the solid carrier surface on which the first specific antibody binding reagent is immobilised, the solid material being readily soluble or dispersible in the liquid sample so that as said solid material dissolves or disperses in the liquid sample, the labelled reagent is released at the same time as the immobilized reagent is exposed to the sample thereby avoiding a spuriously low assay result or hook effect occurring if the analyte is present at high concentration in the sample.

2. A solid phase device which carries immobilised on a surface a specific antibody binding reagent for an analyte, characterised in that a labelled specific antibody binding reagent for the same analyte is contained within a layer of solid material which is applied as a coating superimposed on the surface on which the first specific binding reagent is immobilised, the solid material being readily soluble or dispersible in a liquid suspected of containing the analyte so that as said solid material dissolves or disperses in the liquid sample, the labelled reagent is released at the same time as the immobilised reagent is exposed to the sample thereby avoiding a spuriously low assay result or hook effect occurring if the analyte is present at high concentration in the sample.

3. A solid phase device according to claim 2, characterised in that the solid material is selected from the group consisting of sugars, gelatin, film-forming polymers, starches and dextrans.

4. A solid phase device according to claim 3, characterised in that the solid material is sucrose.

5. A solid phase device according to claim 4, characterised in the specific binding reagents are immunoglobulins.

6. A solid phase device according to claim 5, characterised in that the analyte to which both immunoglobulins are specific is human chorionic gonadotropin or luteinising hormone.

7. A liquid sampling device comprising a first component incorporating a solid surface on which is immobilised a specific antibody binding reagent for an analyte, removably mounted in spaced relationship with an accessory solid surface on an accessory component such that, upon contact with or immersion in a liquid which is to provide a test sample, liquid of the sample contacts the first surface, and the accessory surface acts to retain sample liquid in contact with the first surface after removal of the device from further contact with or immersion in the liquid, characterised in that superimposed on the first surface is a layer of solid material containing a labelled specific antibody binding reagent for the same analyte, the solid material being readily soluble or dispersible in the sample liquid so that as said solid material dissolves or disperses in the liquid sample, the labelled reagent is released at the same time as the immobilized reagent is exposed to the sample thereby avoiding a spuriously low assay result or hook effect occurring if the analyte is present at high concentration in the sample.

8. A liquid sampling device comprising a liquid sampling device as claimed in claim 7, together with means for removing the accessory component from the first component and means for detecting any of the labelled reagent which may have become bound in a sandwich reaction with the immobilised reagent.

9. A liquid sampling device according to claim 8, characterised in that the sampling device comprises a handling piece incorporating a peg on the surface of which is immobilised the specific binding reagent and superimposed on which surface is the layer of solid material containing the labelled specific binding reagent, the peg being located within a removable shroud which provides the accessory surface, the shroud being interlockable with a further component of the test kit to facilitate removal of the shroud from the peg, and the further component also incorporating a well into which the peg can be inserted after removal of the shroud and which well contains one or more reagents to develop the label.