Chemistry: analytical and immunological testing – Biospecific ligand binding assay
Patent
1989-02-03
1992-12-15
Housel, James C.
Chemistry: analytical and immunological testing
Biospecific ligand binding assay
436517, 436518, 436800, 436808, 436 63, 436164, G01N 33566
Patent
active
051716950
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method of measuring the concentration of analytes in liquids using two different labelling markers by immunoassay or immunometric techniques, also to an analytical device and kit.
BACKGROUND ART
It is known to measure the concentration of an analyte such as a drug or hormone in a liquid by exposing the liquid to a receptor having binding sites on its molecule for the analyte, separating the receptor containing bound analyte from the liquid, measuring a value representative of the proportion of the available binding sites on the receptor molecule that have been occupied by analyte molecules (referred to as the fractional occupancy) and comparing that value with a corresponding measured value obtained with a solution of known concentration of the analyte.
The measurement of the value in question can be achieved by a back-titration technique involving contacting the receptor molecule containing bound analyte with a labelled version of the analyte. It is also possible to use, instead of labelled analyte, another labelled material able to occupy only those of the analyte binding sites on the receptor molecule that are not actually occupied by the analyte itself. These two systems are called competitive systems because the labelled analyte or other labelled material competes with the analyte being measured to occupy binding sites on the receptor molecule. In another alternative, the back-titration technique involves contacting the receptor molecule containing bound analyte with a material able to bind with the bound analyte or with only the binding sites occupied by bound analyte, this material being itself labelled or being subsequently labelled by attachment of a labelled marker. This system is known as a non-competitive system because there is no competition for binding sites.
In both the competitive and the non-competitive system the back-titration reagent (analyte or other material) is labelled with a marker. A variety of markers have been used, for example radioactive isotopes (radioimmunoassay), enzymes, chemiluminescent substances and fluorescent markers (fluoroimmunoassay), the latter being either a conventional fluorescent material such as fluorescein or a material which becomes fluorescent only on activation and estimation by time-resolved pulse fluorescence such as a europium or other lanthanide chelate, the magnitude of the fluorescence as revealed on scanning with a high-intensity light beam of appropriate wavelength being a measure of the amount of the labelled material taken up by the receptor molecule containing bound analyte.
Hitherto known assay techniques have depended either on a precise knowledge of the total amount of the receptor present in each sample or on the knowledge that the amount of the receptor remains precisely the same from sample to sample, especially from the unknown sample to the standard samples used for calibration purposes. They have also required an exact knowledge of the total sample volume. These requirements derive from the fact that the measured signal (e.g. fluorescence) in such systems is representative of the total amount of labelled material bound and, provided that not all the labelled material has been bound (in which event the system would be unresponsive to changes in the amount of analyte present), this total amount is dependent not only on the fractional occupancy of the binding sites on the receptor molecule, but also on the amount of receptor molecule present. In short, the fluorescent signal emitted in hithertoknown fluoroimmunoassay techniques has invariably depended in a complex (and, in practice, unknown) manner on the amount of receptor molecule used in the system and on the total amount of analyte present; this implies that both the amount of receptor and the sample volume used must be carefully standardised to ensure correct estimates of the analyte concentration in the test sample, such standardisation being a characteristic and essential feature of all hitherto-known fluoroimmunoassay techniq
Alexander Lyle
Housel James C.
Multilyte Limited
LandOfFree
Determination of analyte concentration using two labelling marke does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Determination of analyte concentration using two labelling marke, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Determination of analyte concentration using two labelling marke will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2092461