{
  "patent_number": "US 4302536",
  "country": "US",
  "title": "How to Detect Disease Markers Using Colored Proteins",
  "original_title": "Colorimetric immunoassay process",
  "summary": "A 1981 method for measuring disease-related proteins in blood by attaching them to naturally colored proteins that can be detected with light.",
  "what_it_does": "This patent describes a way to find specific substances (antigens) in blood or cells by using a special 'tag.' The process involves creating a reagent by chemically bonding an antibody—which naturally seeks out a specific target—to a 'chromoprotein' like ferritin or cytochrome c. Because these chromoproteins have a natural color, they absorb specific wavelengths of light. When the tagged antibody binds to the target in a sample, the resulting mixture can be measured using a standard light-measuring device (colorimeter) to determine exactly how much of the target substance is present.",
  "what_it_does_not_cover": [
    "Does not cover methods using radioactive labels for detection",
    "Does not cover fluorescent markers or labels that require excitation light",
    "Does not cover detection methods that rely on enzymatic color changes rather than the inherent color of the protein",
    "Does not cover the use of synthetic dyes or artificial chromophores"
  ],
  "filed": "1978-08-15",
  "granted": "1981-11-24",
  "expires": "1998-11-24",
  "status": "expired",
  "holder": "Individual",
  "holder_url": "https://patentbrief.org/company/individual",
  "inventors": [
    {
      "name": "Robert W. Longenecker",
      "url": "https://patentbrief.org/inventor/robert-w-longenecker"
    }
  ],
  "times_cited": 27,
  "tags": [
    "biotech",
    "medical_diagnostics"
  ],
  "abstract": "Quantitative and qualitative measurement of antigenic materials present in blood serum or other biological fluids or cells is effected by an extremely precise and sensitive colorimetric immunoassay process. This process comprises adding to the sample to be tested a colorimetric immunoassay agent which comprises an adduct of (1) an antibody for the antigen to be tested and (2) a chromoprotein which is capable of chemically coupling to the antibody by covalent bonding and which chromoprotein imparts to the adduct a characteristic absorbance spectrum in the visible light wavelength range. After reacting this colorimetric immunoassay agent with the antigen to form a reagent-antigen complex, either in the complex-containing fraction or a fraction containing unreacted reagent can be analyzed using standard colorimetric equipment and procedures to provide a fast, simple and direct measurement of the antigen concentration in the sample.",
  "url": "https://patentbrief.org/patent/us/4302536/colorimetric-immunoassay-process",
  "markdown_url": "https://patentbrief.org/patent/us/4302536/colorimetric-immunoassay-process/md",
  "google_patents_url": "https://patents.google.com/patent/US4302536",
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}