Optics: measuring and testing – By shade or color – With color transmitting filter
Patent
1997-12-08
1998-10-13
Evans, F. L.
Optics: measuring and testing
By shade or color
With color transmitting filter
2504581, 2504611, G01N 2164
Patent
active
058220690
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to an apparatus and a method for performing fluorometric measurements, and particularly to a fully automated apparatus for measuring the fluorescence of a fluorescent tag contained in a test sample for allergy assays and which repeatedly measures the fluorescence of different samples under the same conditions and with the same high accuracy.
BACKGROUND OF THE INVENTION
Today allergy assays are made more and more automatically without involvement of any human personnel between different steps of the process. One step in performing an allergy test is to measure the fluorescence of a test sample. This can today be made fully automatically, but there are still many deficiencies.
One common fluorometer for measuring the fluorescence in a sample uses a tray with a plurality of depressions which contain the samples. The tray is inserted into a fluorometer which scans over the samples in order to measure the fluorescence of each sample. One drawback to this fluorometer is that the depressions differ in size and exhibit irregularities which affect the beam path and it is therefore difficult to obtain measurements with high accuracy, since the calibration of the fluorometer has to be carried out in regard to these irregularities and the average size of the depressions.
U.S. Pat. No. 4,447,546 discloses a fluorescent immunoassay apparatus and a method for performing assays, wherein a fluorescent tag capable of emitting fluorescent radiation when excited by more energetic radiation is incorporated into a constituent of an antigen-antibody complex. The apparatus consists of capillary tubing, a fibre and a fluorometer. The fibre has a coating for forming said antigen-antibody complex. The sample to be assayed is drawn into the tubing by capillary action. The depth of the test sample layer on the fibre depends on the incubation time. After the incubation time the fluorometric measurement is then made by using total reflection fluorescence techniques.
The apparatus described in the above U.S. Patent does not work fully automatically, since a person has to bring the optical fibre in the capillary tube to the fluorometer. This could be a source of inaccuracy, since it is not certain that the capillary tube containing the fibre always is lined up in the same way at the fluorometer. A further drawback to this apparatus is that the fibre and capillary tubing are of a disposable type, i.e. a new set of fibre and tubing is used for each new measurement. Thus, this apparatus and method is not directed towards a fully automated system for repeatedly measuring the fluorescence in different samples.
U.S. Pat. No. 4,454,235 discloses an apparatus and a method for transferring fluids in a multi-liquid reagent protocol. Fluid transfer is effected through a capillary tube having a calibrated bore. Once filled the capillary tube holder is then inserted into a second cuvette. The content of the capillary tube is discharged in the liquid of the second cuvette. Assay results are then obtained by inserting the second cuvette and the reaction product of the second regent within a fluorometer.
This apparatus and method also requires manual handling between different steps of the assay. The main object in this patent is to transfer an exact amount of fluid between two cuvettes and the description does therefore not address the problem how to automate the process in order to speed up the time required for performing an assay. Manual handling of course also affects the accuracy of the assay result since the measurements will be made under different conditions.
U.S. Pat. No. 4,548,498 discloses a method and a device for laser induced fluorescence detection in liquid chromatography, in which a beam of light is directed from a laser source towards a liquid flowing in a chosen flow direction for the detection of one or several substances. This invention is directed towards determining which substances are being present in a flowing liquid and does not focus on the problem to automatically measure the
REFERENCES:
patent: 4548498 (1985-10-01), Folestad et al.
patent: 4861163 (1989-08-01), Bach
patent: 5615008 (1997-03-01), Stachelek
Andersson Henry
Bladh Torbjorn
Eriksson Lars
Hedin Bjorn
Evans F. L.
Pharmacia & Upjohn Diagnostics AB
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