Abstract: An apparatus and method for detecting the presence and measuring the concentrations of molecules through a barrier and/or at a distance utilizes the principle of chemical/electrostatic attraction (hereinafter “affinity”), i.e., the affinity between charged atoms and molecules that cause their chemical interactions and reactions, to infer, based on the behavior of molecules on one side of the barrier, the presence and concentration of corresponding molecules on the other side of the barrier. The invention is useful, by way of example and not limitation, in non-invasively measuring glucose levels of diabetic patients.

Abstract: An apparatus and method for detecting the presence and measuring the concentrations of molecules through a barrier and/or at a distance utilizes the principle of chemical/electrostatic attraction (hereinafter “affinity”), i.e., the affinity between charged atoms and molecules that cause their chemical interactions and reactions, to infer, based on the behavior of molecules on one side of the barrier, the presence and concentration of corresponding molecules on the other side of the barrier. The invention is useful, by way of example and not limitation, in non-invasively measuring glucose levels of diabetic patients.

Abstract: An apparatus and method for detecting the presence and measuring the concentrations of molecules through a barrier and/or at a distance utilizes the principle of chemical/electrostatic attraction (hereinafter “affinity”), i.e., the affinity between charged atoms and molecules that cause their chemical interactions and reactions, to infer, based on the behavior of molecules on one side of the barrier, the presence and concentration of corresponding molecules on the other side of the barrier. The invention is useful, by way of example and not limitation, in non-invasively measuring glucose levels of diabetic patients.

Abstract: A method for stabilizing analyses with antibodies and antibody fragments comprises dissolving the analyte in a liquid to form a solution, adding analyte-specific antibodies, fragments of such antibodies, or both to the solution, heating the solution, and then cooling and filtering the solution. The filtered solution may be diluted in a suitable matrix.

Abstract: A stable, single liquid alpha-amylase assay reagent comprises a polysaccharide or long chain oligosaccharide substrate for alpha-amylase having an optically detectable label bonded to the reducing end glucose, by a bond cleavable by alpha- or beta-glucosidase, and a blocking group bonded to the terminal end glucose. The reagent further comprises beta-amylase and either alpha- or beta-glucosidase. Sorbitol is provided in an amount of about 5% to retard degradation of the enzymes. Zwitterionic buffers are also provided to stabilize the enzymes. In preparing the reagent, the enzymes and substrate are filtered through a 0.2 micron or less filter to remove alpha-amylase producing organisms.

Abstract: A method for stabilizing analytes with antibodies and antibody fragments comprises dissolving the analyte in a liquid to form a solution, adding analyte-specific antibodies, fragments of such antibodies, or both to the solution, heating the solution, and then cooling and filtering the solution. The filtered solution may be diluted in a suitable matrix.

Abstract: A stable triglyceride assay solution for use with a chromogen system is comprised of a solution buffered with a Zwitterionic buffering agent and/or TRIS and stabilized with sortibol, gelatin, and ammonium sulfate. Solution pH is in the range of from 6.8 to 8.0. The functional enzymes are lipase, glyercol kinase, and glycerol phosphate oxidase. The preferred chromogen system is based on the inclusion of 4-aminoantipyrine for use in combination with oxidase to yield a detectable chromogen compound.

Abstract: There is provided a stable cholesterol assay composition which comprises an aqueous solution of at least one bile acid or salt thereof being present in an amount of up to about 5 mM; a nonionic surfactant present in an amount of from about 0.15 to about 1.5 percent volume by volume; a buffer in a concentration of from 0 to about 65 mM; and cholesterol oxidase in a concentration of at least about 0.1 KIU/l. Solution pH is from about 5.5 to about 8.5. Addition of cholesterol esterase, phenol, peroxidase and 4-aminoantipyrine provides a total cholesterol chromogen system.

Abstract: There is provided a stable liquid single reagent solution for determination of conjugated bilirubin in biological fluids which comprises an essentially surfactant free aqueous solution containing a positive amount of a water soluble organic sulfate, a diazonium salt, urea and a heavy metal complexing agent, the solution having an acidic pH and stable for at least 18 months at 2.degree. to 8.degree. C. Also disclosed is a method of forming such a reagent.

Abstract: There is provided a stable cholesterol assay composition which comprises an aqueous solution of at least one bile acid or salt thereof being present in an amount of up to about 5 mM; a nonionic surfactant present in an amount of from about 0.15 to about 1.5 percent volume by volume; a buffer in a concentration of from 0 to about 65 mM; and cholesterol oxidase in a concentration of at least about 0.1 kIU/l. Solution pH is from about 5.5 to about 8.5. Addition of cholesterol esterase, phenol, peroxidase and 4-aminoantipyrine provides a total cholesterol chromogen system.

Abstract: There is provided a bilirubin assay composition and method of its formation. The composition comprises water, EDTA, of water soluble organic sulfate present in a concentration of about 1 g/l to solution saturation, caffeine in a concentration of from 0 to about 100 g/l and a diazonium salt in a concentration of about 0.05 to about 1.5 mM. The solution has a pH of from about 3.5 to about 6.0 and is stable for at least 18 months at 2.degree. to 8.degree. C.

Abstract: A method is disclosed for preparing a soluble stable enzyme. The method comprises the steps of reacting in a liquid media an enzyme with a polymer having pendant groups capable of covalently bonding with pendant groups on the enzyme. The enzyme and polymer are mixed with at least one composition which affects the activity of the enzyme. Such a composition can be selected from the enzyme substrate, product of the enzyme substrate reaction, an activator for the enzyme and/or inhibitor for the enzyme. In addition, a composition can be added which can also competitively react with the available pendant groups of the polymer.

Abstract: A stabilized urease solution is disclosed comprising water, buffering agents, a bacteriostat, chelating agent, polyhydroxy organic compound and urease. The preferred buffering agents are selected from low conductivity Zwitterionic buffer salts, such as N-2-hydroxyethyl piperazine-N'-2-ethanesulfonic acid, triethanolamine, tris(hydroxymethyl)aminomethane, diethanolamine, aminomethyl propanol and mixtures thereof.

Abstract: Stabilized enzymes useful in the diagnostic assay of total cholesterol are prepared by combining three separately prepared reagents: (1) a cholesterol esterase reagent; (2) cholesterol oxidase reagent; and (3) a saline diluent reagent. The cholesterol esterase reagent is prepared by dissolving a salt of cholic acid in a buffer solution providing a pH within the range of about 4 to about 9. To this solution is added a cholesterol esterase. The solution is then mixed with a polyhydroxy organic compound and TRITON-X-100. A cholesterol oxidase and a polyhydroxy organic compound are each dissolved in separate portions of buffer solution to make the cholesterol esterase reagent. The saline diluent solution is prepared by dissolving potassium iodide in water and adding a polyhydroxy organic compound. The resultant three reagents, when combined, provide a stabilized enzyme solution having utility in the total cholesterol assay of a serum sample.

Abstract: A stabilized aqueous coenzyme solution is disclosed for use in the clinical assay of a selected biological constituent through the enzymic reaction of an enzyme with a selective substrate for the enzyme and a coenzyme. The aqueous coenzyme solution comprises at least one first enzyme and a first substrate for selectively reacting with the first enzyme in the assay, a coenzyme for interacting with the first enzyme and first substrate in the assay which coenzyme degrades forming a coenzyme conversion product, and at least one second enzyme and second substrate selective for the second enzyme which react with the coenzyme conversion product to regenerate the coenzyme.

Abstract: Stabilized enzymes useful in the diagnostic assay of total cholesterol are prepared by dissolving a salt of cholic acid in a buffer solution providing a pH within the range of about 4 to about 9, to the solution is added a cholesterol esterase. The solution is then mixed with a polyhydroxy organic compound and TRITON-X-100. A cholesterol oxidase and a peroxidase are each dissolved in separate portions of buffer solution and introduced into the buffered solution containing the cholesterol esterase. 4-aminoantipyrine is then added to the solution. The resultant solution is a stabilized enzyme solution which can be used in the total cholesterol assay of a serum sample. The stabilized solution can be used in combination with a chromogen diluent solution which is made by dissolving phenol and TRITON-X-100 in water or a buffer solution. The combination of the stabilized enzyme solution and the chromogen diluent solution provides a solution which has utility in the spectrophotometric assay of total cholesterol.

Abstract: A stabilized urease solution is formulated by blending water, buffering agents, a bacteriostat, chelating agent, polyhydroxy organic compound and urease. The preferred buffering agents are selected from low-conductivity zwitterionic buffer salts, such as N-2-hydroxyethyl-piperazine-N'-2-ethanesulfonic acid, triethanolamine, tris(hydroxymethyl)aminomethane, diethanolamine, aminomethyl propanol and mixtures thereof.

Abstract: A labile, organic reagent, which is unstable in aqueous media and stable in a nonaqueous media, is stabilized by dissolving the organic reagent in a water-miscible, organic solvent which is liquid at room temperature and which is nondegradatively reactive with the organic reagent to form a solution of the organic reagent in the organic solvent. At least 1% of an inert, high-surface area particulate desiccant is added to the solution for entrapping water with the desiccant so that the residual water content of the solution is below about 0.5%. The desiccant can be removed from the solution before sealing it. More than one organic reagent can be added to the solvent, and a solubilizing agent for the organic reagent can be used.

Abstract: Labile coenzymes, such as reduced nicotinamide-adenide dinucleotide (NADH.sub.2), used in biological diagnostic determinations are stabilized by forming a composition of the coenzyme with an organic solvent such as 1,2 propanediol in the presence of at least 1% by volume of a solid, inert hygroscopic agent such as 10% by volume of a molecular sieve material. After stabilization, the inert hygroscopic agent can be removed without materially affecting stabilization of the composition. The stabilized composition shows excellent shelf life and a container in which the composition is stored may be repeatedly opened for use without degradation of the labile coenzymes such as the labile NADH.sub.2.

Abstract: Labile enzymes for use in biological diagnostic determinations are stabilized for long terms by forming a solution of the enzyme in an aqueous media containing at least 20% organic solvent such as 30% aqueous propane diol in the presence of a small amount of polymer such as 0.1% gelatin and then diluting the media at least 20 times with water while maintaining the polymer concentration at least 0.01%. The resultant liquid enzyme composition can be stored for extended periods without loss of significant enzyme catalytic activity. Stability is further enhanced by including from 1 to 18% of salts and 0.1% bacteriastatic agents in the liquid enzyme composition. The liquid enzyme composition enzyme can further contain an enzyme substrate and buffer salts.