Abstract: Methods are disclosed for determining, in a sample derived from a human, the functional activity of a component of the human blood coagulation system, which activity can be correlated to conversion of a substrate specific for activated Protein C (APC), by measuring in an assay medium containing the sample and a substrate for APC, the conversion of the substrate by APC and correlating the conversion to the functional activity of the component. When the component is anticoagulant Factor V, at least one of exogenous APC, Protein S or an inhibitor of Protein S activity is added to the medium. When the component is Protein C, APC, or Protein S, exogenous anticoagulant Factor V or an inhibitor of anticoagulant activity of Factor V is added to the medium. Methods are also disclosed for diagnosing a blood coagulation/anticoagulation disorder or for determining a predisposition thereto in a human by determining anticoagulant Factor V activity in an assay medium containing a sample derived from the human.

Abstract: Methods of detecting antibodies to one or more glycosphingolipid(s) of interest in a sample are disclosed which comprise using a solid-phase reactant having carbonyl groups attached thereon, and the glycosphingolipid(s) of interest linked to the solid-phase reactant by an amide bond between an amino group of the glycosphingolipid of interest and a carbonyl group attached to the solid-phase reactant. The methods of detecting antibodies to glycosphingolipid(s) of interest can be used in methods of diagnosing autoimmune diseases in an individual.

Abstract: A testing apparatus 10 having an absorbent matrix 12, including a membrane 14 which contains a plurality of counter-ions 16. Chromionophore (or fluorionophore)s 18 and affinophores 22 compete to carry ions into the membrane 14 and neutralize the charge of the counter-ions 16. Biological recognition molecules 42 bind to a portion of the affinophores 22 and prevent them from entering the membrane 14, thereby allowing more chromionophore (or fluorionophore)s 18 to enter the membrane 14. The portion of affinophores 22 bound to the biological recognition molecules 42 is inversely proportional to the amount or concentration of analyte 40 occurring within the solution or medium 30. The result of this is that the color of the membrane-covered matrix changes in a manner related to the concentration of the analyte. One application of this apparatus is a strip test for prediction of ovulation.

Abstract: The present invention is drawn to a novel and newly discovered low molecular weight protein fragments that are degradation products of COMP and have a molecular weight of about 14-33 kilodaltons and polyclonal and monoclonal antibodies to the new COMP fragment and other known COMP fragments of molecular weight 67-80 kDa and 150-250 kDa, and thrombospondin fragments (collectivvly referred to as “ADP”) as well as an assay to measure the level of ADP comprising: (1) incubating a body fluid sample, which has been obtained from an arthritis patient, under reducing or non-reducing conditions; (2) incubating the body fluid sample with an anti-ADP antibody; and (3) measuring the level of bound anti-ADP antibody in the body fluid sample. Also disclosed is an assay to measure the ratio of ADP to KS as a diagnostic measure of arthritic disease.

Abstract: The invention relates to methods, kits and systems for determining an analyte in a liquid sample as well as the use thereof for concentration analysis and screening purposes. In one method, a specific binding partner to the analyte is permitted to compete with a conjugate containing the analyte or an analyte analogue for the binding to free analyte. The conjugate also contains a component that specifically binds to a solid support so that reacted and unreacted conjugate are bound thereto when the reaction solution is contacted with the solid support. The amount of analyte is then determined by measuring by a label-free mass-detection technique, such as surface plasmon resonance, the amount of binding partner immobilized on the solid support via the reacted conjugate. This is made possible by the binding partner having a considerably greater mass than the conjugate. Variants of this method are also disclosed.

Abstract: Methods and compositions are described for the detection and quantitation of cardiac specific troponin I and troponin T in samples. Cardiac-specific troponin isoforms exist in various forms in the blood, including free and complexed forms. By selecting antibodies that are sensitive and/or insensitive to these various forms, the present invention can provide immunoassays that more accurately reflect the clinical state of an individual. These described methods and compositions can be used for providing indicators of myocardial infarction and other cardiac pathologies.

Abstract: A chromatographic assay or test device for detection and/or determination of an analyte in a test sample, comprises a base member, and a chromatographic medium located in or on said base member, the base member being provided with a receptacle to receive an applicator having the sample applied thereto, and the applicator being movable when located in said receptacle between a first position in which the applicator is out of fluid contact with the chromatographic medium, and a second position in which the applicator is in fluid contact with the chromatographic medium so as to apply a sample on the applicator to the chromatographic medium. In an alternative aspect, the test device comprises a base member, and a second member, at least one of the base member and the second member including a chromatographic medium, and the second member being slidably movable with respect to the base member from a first position to a second position.

Abstract: An improvement in the immunofixation electrophoresis procedure for detecting proteins in serum, urine or cerebral spinal fluids. Multiple samples from a single patient are placed on a gel and subjected to electrophoresis for resolving or separating proteins. A container has multiple receptacles which store, separately, various antisera. The separate antisera are withdrawn from the receptacles and simultaneously applied to the sample areas for subsequent incubation. The receptacles are preferably arranged in multiple series in the container, each series offset from, and partially overlapping, the receptacles of the next series.

Abstract: This invention relates to binding protein assays. In particular, this invention relates to binding protein assays for B12 and folate in serum or plasma. More specifically, this invention provides a sequential assay that uses a combination of specific binding proteins, and anti-binding protein antibodies to measure B12 and folate in serum or plasma.

Abstract: The full amino acid and DNA sequences of placental protein 13 (PP13) are disclosed. Also described are various PP13 derived peptide fragments, and a recombinant method for the production of PP13. PP13 may be used in a screening and a diagnostic method for pregnancy-related complications.

Abstract: Molecules, such as antibodies, with binding specificity for Tissue factor Inhibitor (TFI) or for polypeptides comprising one or more Kunitz domains of TFI can be used in methods to detect TFI or polypeptides containing a Kunitz domain of TFI in biological fluids. Either direct or indirect detection methods can be carried out.

Abstract: Compositions and methods of use thereof for capture and detection of selected molecules are described. In one embodiment, a first composition includes a ligand component, such as an antibody coupled to a nucleic acid component. An a preferred embodiment, the nucleic acid is labeled with a fluorescent marker to facilitate detection. Another aspect of the invention is the ligand component bound to a solid support via a complementary nucleic acid component and a linker moiety. The method involves binding the target with the first composition in free solution, then binding the target to the solid support by means of both DNA hybridization and antibody-antigen affinity binding. Unbound molecules are washed away, and then the bound targets are detected by fluorescence detection. Vital stains can also be used to detect viable cells.

Abstract: The invention relates to capillary electrophoretic methods for detecting ligands or hit compounds that can bind to a selected target at or above a selected binding strength. The method allows one to rank various ligands based on their relative affinity, i.e., the relative stability of the target/ligand complex during capillary electrophoresis under selected conditions. The method also enables selective detection of strong-to-moderate binding hit compounds, even in the presence of high concentrations of weaker, competitive hit compounds.

Abstract: An assay device, a fluid analyte sample separator device and methods for use of thereof for determining whether the integrity of a fluid analyte sample has been compromised and for contemporaneously assaying the sample for the presence or absence of multiple analytes, such as drugs of abuse. The device is composed of a housing having separate slots therein for insertion of one or more analyte test strips, one end of which protrudes from the housing, and one or more units of a sample integrity monitoring system. The device may be used in dipstick or cassette form. An analyte sample separator for division of sample and retention of uncontaminated sample for further testing is also provided. The analyte test strips and sample integrity monitoring system are replaceable, so that the panel of analytes and of sample condition parameters tested can be customized.

Abstract: An improved method for detecting antibodies is disclosed. The method employs a recombinant denatured bacterial enzyme. The invention also relates to a test kit useful for performing an immunoassay which comprises a container containing a denatured recombinant bacterial enzyme.

Abstract: A biological fluid collection container comprising a cup member, a lid assembly removably mounted to the cup member comprising a housing with a downwardly extending cylindrical skirt, a luer lock with a throughgoing bore extending from one side of the lid housing. A hollow tube extends from the other side of the lid housing adjacent the luer lock and is axially aligned with the throughgoing bore of the luer lock. The hollow tube is provided with a plurality of throughgoing holes leading into its lumen along its surface to provide for a sampling along various liquid level layers of the biological fluid specimen collected in the cup member so that when the biological fluid specimen is removed from the cup member a representative sampling is obtained.

Abstract: A system and method for removing contaminants from a surface. The system is designed to use particles having means thereon which are capable of selectively binding to a contaminant or contaminants of interest. The particles are applied to the surface whereupon the contaminants bind to the particle. When the particle is removed, the desired contaminants are also removed. Preferably, the present invention utilizes magnetic particles having iron therein. The particles may then be readily removed using magnets. The means for binding the contaminant to the particle preferably comprise a ligand or a charge specifically designed to remove the contaminant of interest. The particles may be included in a carrier to facilitate their application to the surface. The invention is especially useful for the removal of contaminants from skin.

Abstract: Disclosed is a method for determining alcohol intake or alcohol induced liver damage in a subject by quantifying the content of sialic acid in apolipoprotein J (Apo J). In particular the present invention involves the steps of (a) providing a sample containing Apo J from a subject; (b) purifying the Apo J from the sample; (c) determining sialylation index, i.e., moles of sialic acid peer mole of Apo J in the sample; and (d) evaluating whether the sialylation index is an indication of alcohol intake or alcohol related liver damage recovery from alcohol addiction or alcohol relapse in the subject.

Abstract: A lateral flow testing device is provided for testing a biological fluid for the presence of methamphetamines. The device includes a substrate element such as a nitrocellulose strip, including an antibody zone and an immobilized drug conjugate zone for detecting presence of methamphetamines, and an on-board chemical reactant for preventing undesirable cross-reactivity to ephedrine and/or pseudoephedrine that may be present in the biological fluid being tested. Preferably, the on-board chemical reactant is sodium periodate. Methods for preparing test devices are provided including the step of striping a substrate sheet with a solution containing sodium periodate during manufacture of methamphetamine lateral flow test strips.

Abstract: A competitive binding assay kit and process for the immunological detection of a blood antigen of specified phenotype (for example phenotypes of human platelet antigen HPA) in a sample of whole blood. The kit contains a substrate having purified blood antigen of specified phenotype immobilized thereon, antibody specific to said blood antigen and means for enabling detection of antibody bound to said blood antigen. The process comprises mixing a sample of whole blood with a predetermined amount of antibody, so as to bind the antibody to any antigen present in the sample of whole blood and bringing the mixture into contact with the immobilized antigen so as to bind any remaining unbound antibody to the immobilized antigen, and determining the amount of immobilized complex and consequently the specified blood antigen phenotype.

Abstract: The invention concerns a method for the immunological determination of an analyte in a sample using magnetic particles coated with the analyte to be determined or analyte-specific bonding partners and directly detectable non-magnetic particles coated with analyte-specific bonding partners or the analyte to be determined or using a non-magnetic substance which is indirectly detectable, and incubation of the reaction mixture. The method is characterized in that the magnetic particles are subsequently separated from the reaction mixture using a magnetic test strip and the analyte concentration is determined directly.

Abstract: A test device, system and method, the device composed of an elongated, toothbrush-shaped, transparent, plastic housing and a lateral-flow test strip for the detection of an analyte, such as a beta-lactam in milk, in the housing, the housing having an expansion cavity to receive expanded, liquid-contacted, absorbing material in the test strip, and to control lateral flow rate and times in the test strip.

Abstract: Antigens for the detection of antibodies to Neospora parasites for the diagnosis of neosporosis have been identified. Recombinant antigens may be produced by expression of DNA sequences derived from Neospora caninum. Both antigens are capable of detecting antibody responses in animals experimentally inoculated with N. caninum but show no evidence of cross-reactivity with serum from animals inoculated with closely related parasites such as Toxoplasma gondii or Sarcocystis species.

Abstract: Device for assaying an analyte, comprising a labelling zone, where a label can bind to the analyte, in communication with a capture zone, wherein the pore size of the capture zone is such that label which is not bound to the analyte can migrate therethrough, whereas label which is bound to the analyte cannot. During migration from the labelling zone (large pore size) to the capture zone (small pore size), unbound label can pass into and through the capture zone, whereas bound label will be captured at the junction of the labelling zone a the capture zone. The device relies upon the label being smaller than the analyte, such that free label is not retarded by the capture zone. It is particularly suitable for assying analytes such as spermatozoa, which are large in comparison with a label such as a labelled antibody.

Abstract: The invention provides monoclonal antibodies which are reactive with fibrin(ogen) degradation products (FDPS) generated by matrix metalloproteinases (MMPs), such as MMP-3, MMP-7, and membrane-type 1, MT1-MMP proteolysis of fibrinogen and cross-linked fibrin (and not plasmin or other proteases). Monoclonal antibodies of the invention include, but are not limited to, H5, F2, 90/2, 90/5, B4, 13, C6, A6, G6, E6, 197-1 and 197-2. This invention also provides methods of using monoclonal antibodies for detection of FDPs generated by proteolysis of fibrin(ogen) by MMPs, such as MMP-3, MMP-7, and MT1-MMP. In addition, the present invention provides methods for diagnosing rheumatoid arthritis, osteoarthritis, and synovitides, as well as angiogenesis, atherosclerosis, renal diseases, malignancy and inflammation.

Abstract: A multi-slide assembly includes various components that alone or in combination facilitate testing of test samples with minimal manipulation of assay components. Moreover, the various device components permit centrifugation, culturing and analysis of each test sample to be performed in the same assembly. A frame retains a plurality of reaction vessel assemblies between a pair of opposing channels that are configured to slidably receive the opposing ends of each reaction vessel assembly. A strip cap seals the openings in each reaction vessel using cap members having sealing rings circumscribing the external walls thereof to form compression seals with internal walls of the reaction vessels. Furthermore, in a method of making a multi-well slide assembly, an ultrasonic welding process removably bonds a plurality of wells to a slide plate to provide an adequate seal therebetween during centrifugation, yet still enable separation thereof by an operator.

Abstract: A bacteriophage linked to an enzyme can replace an antibody in a system for detecting the presence of a bacteria in a sample. Specifically Brucella abortus (a pathogen which causes brucellosis in cattle) can be detected using Brucella bacteriophage for the virus, urease for the enzyme linked to the bacteriophage, m-maleimidobenzoyl-N-hydrosysuccimide ester as a coupling reagent, sera from mice immunized with Brucella bacteriophage for a detector antibody, urease conjugated to anti-mouse sheep antibody for an indicator, and urea with bromcresol purple as the substrate. The materials can be used in indirect (sandwich) or direct enzyme-linked viral assays (ELVirA).

Abstract: The invention concerns the stabilization and amplification of electrochemiluminescence signals in detection methods.

Abstract: Many of the effects of nitric oxide are mediated by the direct modification of cysteine residues resulting in an adduct called a nitrosothiol. A method to detect proteins which contain nitrosothiols involves several steps. Nitrosylated cysteines are converted to tagged cysteines. Tagged proteins can then be detected, for example, by immunoblotting and/or can be purified by affinity chromatography. The method is applicable to the detection of S-nitrosylated proteins in cell lysates following in vitro S-nitrosylation, as well as to the detection of endogenous S-nitrosothiols in selected protein substrates.

Abstract: The invention provides a method of reducing the proliferation of a neoplastic cell. The method consists of contacting the neoplastic cell with a cytotoxic or cytostatic binding agent specifically reactive with an aberrantly expressed vesicular membrane associated neoplastic cell specific internalizing antigen. The neoplastic cell specific internalizing anitgen can be selected from the group consisting of lamp-2 and limp II families of lysosomal integral membrane proteins. Also provided is a method of intracellular targeting of a cytotoxic or cytostatic agent to a neoplastic cell population.

Abstract: The invention relates to the removal of viruses from aqueous solutions, as a rule protein solutions, by ultrafiltration. This entails the viruses to be removed being increased in size by incubation with a high molecular weight receptor binding thereto, preferably a specific antibody, so that, on the one hand, the separation effect is improved and, on the other hand, a larger pore diameter which can now be chosen for the filters used also makes it possible for smaller viruses to be separated from larger protein molecules present in protein solutions, and, where appropriate, the filtration rate is increased.

Abstract: The present invention provides a method for the quantification and assessment of platelet activation in whole blood samples and monitoring of antiplatelet pharmacologic agents. The method for quantifying platelet activation includes exposing platelets to a physiological concentration of an agonist that activates some of the platelets, resulting in the formation of at least one binding site on the surface of the activated platelets, and measuring the activated platelets. The present invention provides a method of assessing specific components of platelet activation.

Abstract: A method and apparatus for the manipulation of colloidal particulates and biomolecules at the interface between an insulating electrode such as silicon oxide and an electrolyte solution. Light-controlled electrokinetic assembly of particles near surfaces relies on the combination of three functional elements: the AC electric field-induced assembly of planar aggregates; the patterning of the electrolyte/silicon oxide/silicon interface to exert spatial control over the assembly process; and the real-time control of the assembly process via external illumination. The present invention provides a set of fundamental operations enabling interactive control over the creation and placement of planar arrays of several types of particles and biomolecules and the manipulation of array shape and size. The present invention enables sample preparation and handling for diagnostic assays and biochemical analysis in an array format, and the functional integration of these operations.

Abstract: The present invention is directed to methods for analyzing one or more fluid samples for the presence, amount or identity of one or more analytes optionally present in said samples, which uses a device having one or more round wells with a fixed diameter, the wells exposing a substrate of a specific thickness, whereby the substrate has oriented through going channels, in the area of the substrate exposed in the well is provided with at least one binding substance specific for a least one of said analytes. Using the device the sample fluid is forced to pass through the channels in the substrate from the upper side of the substrate to the lower side of the substrate and back at least one time, under conditions that are favorable to a reaction between any analyte present in the sample and the binding substances.

Abstract: The invention relates to a method of evaluating the immunological status of a subject comprising the steps of 1) determining the content of an antibody in a liquid sample from the subject using an immunoassay, wherein the reaction between the antibody of the sample and a ligand in the form of an antigen, an antibody or a hapten, the ligand being directed to the Fab region of the sample antibody, is carried out in the presence of other constituents of the sample to obtain a measurement 1, 2) determining the content of an antibody in the liquid sample using an immunoassay, wherein the reaction between the antibody of the sample and a ligand in the form of an antigen, an antibody or a hapten, the ligand being directed to the Fab region of the sample antibody, is carried out in the absence of other constituents of the sample to obtain a measurement 2, and 3) interrelating measurements 1 and 2 to express the interference and using the interference as a parameter for evaluating the immunological status of the subje

Abstract: A chromatographic strip positive readout binding assay device and method suitable for quick, sensitive and reliable field testing for small molecules such as environmental contaminants, drugs of abuse, therapeutic drugs and hormones. The detectable label is not attached to either the analyte or to the analyte receptor. Low affinity binding pairs can be used in the positive readout binding assay.

Abstract: Magnetic particles for separating biological mixtures consist of nacreous luster pigments with magnetic properties coated with a biological polymer.

Abstract: A highly sensitive assay is disclosed which combines immunomagnetic enrichment with multiparameter flow cytometric and immunocytochemical analysis to detect, enumerate and characterize carcinoma cells in the blood. The assay can detect one epithelial cell or less in 1 ml of blood and has a greater sensitivity than conventional PCR or immunohistochemistry by 1-2 orders of magnitude. In addition, the assay facilitates the biological characterization and staging of carcinoma cells.

Abstract: Separation apparatus and method for separating magnetic and/or magnetically-labeled particles from a test medium in a reaction chamber which incorporates baffles, a spinner, a stirrer, or a plunger operable to be displaced along a collection surface to define a narrow flow path through which the particle-laden test medium must flow. The collection surface is a thin-walled non-magnetic material having a plurality of magnetic pole faces positioned therearound. Test medium within a reaction chamber is caused to flow past a collecting surface, and a high-gradient magnetic field is applied to the surface to capture magnetically responsive particles in the test medium. The particles are deflected toward the collection surface in the flow path for the test medium. The narrow flow path assures that substantially all of the particles pass within the high-gradient magnetic field along the collection surface.

Abstract: A bacteriophage linked to an enzyme can replace an antibody in a system for detecting the presence of a bacteria in a sample. Specifically Brucella abortus (a pathogen which causes brucellosis in cattle) can be detected using Brucella bacteriophage for the virus, urease for the enzyme linked to the bacteriophage, m-maleimidobenzoyl-N-hydrosysuccimide ester as a coupling reagent, sera from mice immunized with Brucella bacteriophage for a detector antibody, urease conjugated to anti-mouse sheep antibody for an indicator, and urea with bromcresol purple as the substrate. The materials can be used in indirect (sandwich) or direct enzyme-linked viral assays (ELVirA).

Abstract: An assay device and method are provided which allow the determination of the presence or absence of at least one analyte in a test sample, while providing specific identification of the test subject. The assay device includes a reaction medium having at least one reaction zone and at least one control zone, which is capable of providing a pattern suitable for identifying the test subject. The pattern suitable for identifying the test subject is preferably a fingerprint. In a preferred embodiment of the invention, the reaction zone and the control zone include at least one member of a ligand/receptor pair.

Abstract: The invention relates to an immunochemical method for detecting deposit of Bacillus thuringiensis delta-endotoxin or pesticidally-active fragment thereof on a plant or tree. The invention further relates to kits for using such a method.

Abstract: The present invention relates to a method for at least one of detecting, quantifying or isolating at least one analyte from a liquid medium in which the analyte is distributed and comprises providing a reagent comprised of particles having a receptor for an analyte fixed to the particles distributed in the medium and a capturing means having an exposed surface defining an active zone. An intermediate reagent is formed by the complex of the reagent with the analyte. A second receptor is fixed in the active zone to capture either the analyte bound by the reagent or the receptor (capture partners). The active zone serves as a site of isolation and concentration of the capture partners.

Abstract: Assay methodology of the invention allows for: (1) determining if a sample contains a conformation of a protein which is associated with disease and the concentration and amount of such if present; (2) determining the amount of protease resistant disease related protein in a sample and by subtracting that amount from the total amount of disease related protein present determining the amount of protease sensitive disease protein in the sample; and (3) determining the strain and incubation time of a disease related protein by (i) relating the relative amounts of protease resistant and protease sensitive protein to known strains to thereby determine the strain; and (ii) plotting the concentration of protease sensitive protein on a graph of incubation time versus concentration of protease sensitive protein for known strains to predict the incubation time of an unknown strain of pathogenic protein in a sample.

Abstract: The invention provides a human microfibril-associated glycoprotein 4 splice variant (MAG4V) and polynucleotides which identify and encode MAG4V. The invention also provides expression vectors, host cells, antibodies, agonists, and antagonists. The invention also provides methods for treating or preventing disorders associated with expression of MAG4V.

Abstract: Microporous solid phase materials that are suitable for lateral flow and other assays for detecting the presence of analytes in test samples, that are stable under variations in humidity and, even after storage for extended periods of time, can form stable covalent bonds with molecules containing a free primary or secondary amine group or sulfhydryl group are described. The invention further concerns chemically derivatized solid phase materials, and conjugates comprising such materials. Examples of lateral flow devices for the quantitative or semi-quantitative determination of an analyte in a biological sample are described.

Abstract: The invention relates to methods of determining the presence or amount of an analyte in a sample suspected of containing the analyte, said method comprising the steps of: (a) bringing together in an aqueous medium to form a mixture: (i) the sample; (ii) at least one specific binder for the analyte; (iii) a first binding agent coupled to either (1) exogenous analyte or (2) the specific binder for the analyte; (iv) a support comprising a second binding agent; b) adding an activator to the mixture, wherein the activator binds the first binding agent and the second binding agent of the support to immobilize the first binding agent; c)determining the amount of the analyte in the sample by detecting the immobilized first binding agent, the presence or amount thereof being related to the presence or amount of the analyte in the sample.

Abstract: A apparatus for assaying glycated proteins and other analytes in biological samples such as blood, in which a sample is presented to the apparatus, includes an inlet port between moveable between first and second inlets, such that the inlet can be brought into liquid communication with each inlet in turn. The inlet port accommodates a filter or binder. The apparatus also includes a microprocessor operable via a key pad, at least one light emitter and at least one light detector, a display and driver, and an A to D converter, and is operatively connected to a power source.

Abstract: This invention relates to a competitive-binding, capillary electrophoretic method of detecting new therapeutic regulatory (modulating) and diagnostic compounds in natural samples and other complex biological materials. The present method generally comprises mixing a preselected, detectable target with a sample of complex biological material to produce a first, sample/target mixture capillary electrophoresis apparatus. Subsequently, the first mixture is mixed with a pre-selected, tight-binding competitive ligand (TBCL), prior to produce a second, sample/target/TBCL mixture, for a predetermined optional incubation period sufficient to allow the TBCL to bind a pre-selected percentage of the available target in the absence of any other ligand. An aliquot of the second mixture is subsequently subjected to pre-optimized capillary electrophoresis, during which the migration of the target is monitored.

Abstract: A living body component in a sample derived from a living body can be rapidly and accurately measured by reacting the sample with a reagent comprising a combined product of an affinity substance and a polypeptide having at least three acid residues derived from a strong acid, separating the resulting complex by a method applying negative change such as using an anion-exchanger, and determining the amount of the analyte to be measured, on the basis of the amount of the complex or free combined product.