Resin from wood of certain species of GUAIACUM. It is used as clinical reagent for occult blood.

Chemical, spectroscopic, or microscopic detection of extremely small amounts of blood.

Field of chemistry that pertains to immunological phenomena and the study of chemical reactions related to antigen stimulation of tissues. It includes physicochemical interactions between antigens and antibodies.

A sodium salt of gold thiosulfate. It has uses like the ORGANOGOLD COMPOUNDS.

Endoscopic examination, therapy or surgery of the luminal surface of the colon.

Tumors or cancer of the COLON or the RECTUM or both. Risk factors for colorectal cancer include chronic ULCERATIVE COLITIS; FAMILIAL POLYPOSIS COLI; exposure to ASBESTOS; and irradiation of the CERVIX UTERI.

Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)

Organized periodic procedures performed on large groups of people for the purpose of detecting disease.