Abstract: A sac, in particular a vesicle, having a detectable metal, in particular a rear earth metal, encapsulated therein. The sac may be sensitized with a ligand and used in an assay. The vesicle is stored and/or used in an aqueous solution which includes the rare earth metal to increase the concentration of metal in the sac.

Abstract: Liposomes are formed from compounds including a phosphonate or phosphinate group instead of a phosphate group. The liposomes bind to enzymes, such as a phospholipase, and such liposomes containing a detectable marker may be used as a substrate in an enzyme immunoassay.

Abstract: A method for determining the percentage of glycosylated hemoglobin in the total hemoglobin of a blood sample includes binding of both glycosylated and nonglycosylated hemoglobin competitively to a nonspecific binder for hemoglobin affixed to a dipstick and reacting the glycosylated hemoglobin with a dihydroxyboryl reagent conjugated to a fluorescent dye. When the binding and reacting steps are complete, the dipstick is washed and its color is measured by absorption of incident light having a wavelength within the absorption range of hemoglobin as an indication of total hemoglobin in the sample. Incident light having a wavelength within the absorption range of the dye is then applied to the dipstick and fluorescence from the dipstick is measured as an indication of glycosylated hemoglobin. The measurements may be made with a reflectometer capable of computing the percentage of glycosylated hemoglobin in the sample from the color and fluorescence measurements.

Abstract: A sac is produced by use of a compound which includes a hydrophobic portion and a polar group which is hydrolyzable by an enzyme and which is spaced from the hydrophobic portion by a hydrophilic portion which does not have a polarity sufficient to form a vesicle. A detectable marker may be released from the sac by use of a hydrolase enzyme, whereby the sac may be used as a substrate in an enzyme assay.

Abstract: A method for determining glycosylated hemoglobin in a diluted blood sample includes binding of glycosylated hemoglobin to a specific monoclonal antibody and binding of nonglycosylated hemoglobin to a polyclonal antibody. The polyclonal antibody binds to all hemoglobin fractions and blocks the peroxidase activity thereof, except glycosylated hemoglobin bound to the monoclonal antibody which retains peroxidase activity. A beam of light having a wavelength of about 416 nm is passed through the assay medium and is absorbed by all hemoglobin fractions, bound or unbound, and this absorbance thereby provides a measure of total hemoglobin. Hydrogen peroxide and a peroxidase substrate are added. The substrate is oxidized by the peroxide to a product having an absorbance at a wavelength different from 416 nm, the oxidation being catalyzed by the retained peroxidase activity of the bound glycosylated hemoglobin. This absorbance provides a measure of glycosylated hemoglobin.

Abstract: Solid phase assay for an analyte wherein binder is supported on a solid support, such as nitrocellulose, and the tracer is comprised of ligand labeled with a particulate label, such as a liposome, including a detectable marker which is not visible.

Abstract: Sacs comprising a compound having a hydrophilic peptide radical are prepared and are believed to have improved stability as a result of hydrogen bonding. The sacs, including a detectable marker and derivatized with a ligand may be used as a tracer in an assay.

Abstract: Vesicles are formed, in part, from an amphiphilic chelating agent whereby a detectable metal marker can be complexed to the vesicle. A portion of the vesicle may also be formed from an amphiphilic compound derivatized with a ligand, whereby the vesicle may be used as a tracer in an assay. If the detectable metal marker is a fluorescent rare earth metal, the assay may be a time delay fluorescent assay. The vesicles may be dried, and reformed by addition of water for use in an assay.

Abstract: Solid phase assay for an analyte wherein binder is supported on a solid support, such as nitrocellulose, and the tracer is comprised of ligand labeled with a colored particulate label, such as a liposome including a dye. The assay has a high sensitivity, and the tracer is visible on the support under assay conditions, whereby tracer can be determined, without instrumentation, and without further treatment thereof.

Abstract: Vesicles are formed having a detectable marker and ligand conjugated to compounds forming the vesicle wall. The vesicles are dried, and reformed by addition of water for use in an assay.

Abstract: A sac, in particular a vesicle, including as a detectable marker an absorbing dye having an extinction coefficient of at least 100,000 and a solubility in water of at least 0.1M; in particular, sulforhodamine B or salt thereof. The sacs have improved stability to leakage and are useful in a variety of assays; in particular, when sensitized with a ligand.

Abstract: A method for separation-free solid phase immunoassay of an analyte includes contacting an anti-analyte attached to the surface of a solid support with the analyte, a light absorbing material and a fluorescent tracer for the analyte. The resulting mixture is incubated. The method includes applying excitation light to the mixture and time resolved measurement of fluorescence emission from the tracer. All excitation light and fluorescence emission are absorbed by the light absorbing material except that absorbed and emitted by the tracer bound to the anti-analyte whereby the only fluorescence emission detected is from the bound tracer. Since free tracer in the fluid phase of the assay medium does not emit fluorescence, separation of the bound and free fractions is unnecessary. The invention includes a kit of materials useful in performing an immunoassay in accordance with the method of the invention.

Abstract: In an assay for an analyte, the tracer is comprised of a sac lysing agent, which lyses sacs containing detectable marker and sac lysing agent in inactive form which is activated when released from the sacs to provide a cascade effect which increases sensitivity.

Abstract: In a homogeneous assay, binder supported on a solid support, having a sac lysing agent conjugated thereto, is contacted with analyte and tracer comprised of sacs containing a detectable marker. The sacs of the bound tracer portion are lysed to release marker to determine analyte in the sample.

Abstract: Homogeneous assay for determining thyroid binding capacity by use of a fluorescent T.sub.3 tracer, such as T.sub.3 coupled to a fluorescein dye through a radical derived from L-lysine.

Abstract: A chromogen, in particular, a fluorescent compound, is conjugated to a ligand through an amino acid spacer radical, which includes a free carboxyl group. The tracers are particularly suitable for use in a flow through assay for low molecular weight analytes. The tracers are rapidly bound, of good sensitivity, and low non-specific binding.

Abstract: An improved immunoassay method for determining thyroid stimulating hormone (TSH) in a liquid sample wherein the bound- and free-species of the labelled, preferably radio-labelled, TSH are separated by contacting the liquid reaction mixture with Florisil adsorbent which selectively adsorbs free TSH and physically separating the adsorbent from the liquid mixture. The Florisil adsorbent is preferably contained in a column form. A test kit for performing the improved method is also provided. The assay is more simple and less time consuming than the prior art techniques.

Abstract: A dry radioimmunoassay test composition comprising a mixture of a radiolabelled form of a ligand, i.e., a hapten or an antigen, an antibody for the ligand, and a heavy metal cation, e.g., cupric ion, to inhibit the complex-forming reaction between the radiolabelled ligand and the antibody. A method for preparing the dry test composition is also provided. In use in a radioimmunoassay, the dry test composition is reconstituted with an aqueous liquid and combined with a test sample and a chelating agent to bind the heavy metal cation, permitting reaction among any ligand present in the sample, the radiolabelled ligand, and the antibody. A test kit for performing such radioimmunoassay is also provided.

Abstract: A specific binding assay method, and a test device and test kit for use therein, for determining a liqand, such as an antigen or antibody, in, or the ligand binding capacity of, a liquid medium, particularly a body fluid such as serum, wherein the unknown ligand competes with a labeled component, such as a radiolabeled form of the ligand or of a binding analog of the ligand, for binding with a binding partner, and wherein separation of the resulting bound-species and free-species of the labeled component is accomplished by allowing the liquid reaction mixture to be drawn by capillary action into a column comprising a bed of an adsorbent material selective for one of the two species. The improvement comprises using a column containing at least one additional bed of capillarily absorbent material disposed above said adsorbent bed and which is substantially nonadsorbent relative to the one of said two species which said adsorbent bed selectively binds.

Abstract: A specific binding assay method and test kit for determining a ligand, such as an antigen or antibody, in, or the ligand binding capacity of, a liquid medium, particularly a body fluid such as serum, wherein the unknown ligand competes with a labeled component, such as a radio labeled form of the ligand or of a binding analog of the ligand, for binding with a binding partner, with the improvement that separation of the resulting bound-species and free-species of the labeled component is accomplished by drawing the liquid reaction mixture into a column of an adsorbent material selective for one of the two species. Separation results by immobilization of the selected species at the beginning portion of the adsorbent column while the other species is transported farther along the column by advance of the reaction mixture.