Optics: measuring and testing – Plural test
Reexamination Certificate
2000-10-06
2004-09-14
Evans, F. L. (Department: 2877)
Optics: measuring and testing
Plural test
C356S416000, C356S337000
Reexamination Certificate
active
06791676
ABSTRACT:
The present invention relates to a method and an apparatus for the essentially simultaneous performance of spectrophotometric and nephelometric analyses principally in in-vitro diagnosis.
While on the one hand an increasing demand for more sensitive optical detection methods for automated in-vitro laboratory analysis has evolved in recent years, at the same time requirements for increasing alignment and harmonization of the analytical methods have been instituted.
These requirements can be comprehended against the background of the concentration of the number of measurement laboratories in the form of a few centers for laboratory diagnosis. Only by more extensively matching the analytical methods and reducing the number of different equipment variants or method conditions can the tests be carried out simply and without increased operational requirements. These endeavors are thereby intended to result in further cost savings in the field of diagnosis.
The need for more complex, fully automated analysis equipment is growing at the same time. In order to be able to process a multiplicity of different samples and types of samples and to achieve the required throughput, said analysis equipment is additionally coupled via corresponding networks to laboratory integration systems for discontinuous tracking of sample, test or consumable material.
Capital expenditure and subsequent capacity utilization of such fully automated analysis machines can only be achieved, however, if at the same time there is also harmonization in analysis in the different fields of application of in-vitro diagnosis. Thus, even now, attempts are being made to implement inter alia parameters of clinical chemistry, plasma protein diagnosis or immunochemical diagnosis on common platforms. This is successful particularly when the requirements made of the process technology in the different fields of application are similar. This is because the conditions for the treatment of samples or of reagents solutions with regard to storage (temperature stability) or metering (volume, precision) often correspond well.
Thus, the increasing matching and harmonization should also consistently extend to the detection methods used for analysis.
Most of the analytical methods employed at the present time only use a way of obtaining measurement data of the kind offered by photometry or light scattering. In certain analysis methods, the light scattering is detected at different angles or under different angular ranges. Scattered-light methods are extremely sensitive and their resolution is superior to that of photometric methods particularly for methods in which the formation and temporal change of scattering centers are detected, as is the case in agglutination tests or in methods of particle-enhanced in-vitro diagnosis. Comprehensive considerations and calculations concerning the theory of scattered light are adequately known per se to the person skilled in the art and are textbook material (thus, for example, C. F. Bohren, D. R. Huffman, Absorption and Scattering of Light by Small Particles, J. Wiley & Sons, 1983). Further aspects of application to in-vitro diagnosis tests may be found inter alia in E. P. Diamandis et al. 1997 (Immunoassay, Academic Press, 1997, Chapter 17: Nephelometric and Turbidimetric Immunoassay) and the references cited therein.
On the other hand, the requirement for many test methods consists of carrying out photometric tests which purely detect absorption. The scattered-light signal fails in these cases since, at best, the contaminants contained in the material to be measured can be measured.
By way of example, DE-A 2409273 and U.S. Pat. No. 4,408,880 describe methods in which a sample is excited by a laser beam and its scattered light is detected at an angle outside the beam axis of the incident light. The scattered light used for the measurement is masked out by a suitably shaped annular diaphragm which retains the excitation light from the laser.
U.S. Pat. No. 4,053,229 likewise describes an apparatus for measuring scattered light, in which a scattered light measurement is effected simultaneously at an angle of 2° and at an angle of 90°.
WO 98/00701 describes a combination of a nephelometer with a turbidimeter which comprises two light sources. While one of these, in the form of a laser, produces the scattered light which is detected at 90°, a diode (LED) emitting in the infrared spectral region serves for measuring the turbidity on the axis of the incident light. The method described in the application serves in particular for improved control of the intensity of the laser used.
To date, there are no known methods and/or apparatuses which enable both scattered-light measurements and photometric measurements to be carried out essentially simultaneously.
The present invention was thus based on the object of finding an apparatus permitting essentially simultaneous spectrophotometric and nephelometric measurement in a sample within one assembly.
Essentially simultaneous means that the measurement points of the spectrophotometric determination and those of the nephelometric determination succeed one another in time as closely as is necessary for the type of measurement. In the case of kinetic measurements, the time interval will need to be shorter than, for example, in the case of end point measurements in which the time interval of the measurements is essentially determined by the mechanical size of the rotational/translational movement of the measurement cell in relation to the measurement location. In the case of kinetic measurements, on the other hand, the time interval must be as short as possible.
The present invention describes an apparatus allowing a combination of methods for carrying out in-vitro diagnosis analyses based on the principle of scattered-light measurement and of spectrophotometry.
In this case, the measurement unit enables methods of photometry and of scattered-light measurement to be employed essentially simultaneously. Light from one or more light sources
1
,
2
is guided via one or more light guidance arrangements
3
to the common beam axis
24
and then via the common beam axis to the reaction location
11
. Scattered light or photometric signal can be detected by means of sensors
17
and a spectrophotometer
25
. Pulse driving means that the two methods are decoupled temporally such that no reciprocal influencing or interference occurs during operation.
While nephelometry is used predominantly for the analysis of agglutination tests and in particle-enhanced immunodiagnosis, photometry serves for measuring numerous other clinical-chemical parameters based on spectral changes. The combination makes it possible to achieve the aim of being able to carry out a multiplicity of different diagnostic tests pertaining to clinical chemistry, immunodiagnosis, plasma protein diagnosis or coagulation diagnosis on a single module. The present description relates to the field of the use of automated measurement systems in analysis and in in-vitro diagnosis. In particular, the apparatus described makes it possible to simultaneously carry out tests which are measured with the aid of scattered-light measurement and/or by photometry in the UV-Vis spectral region.
In particular, the unit can be integrated in systems in which the measurement of a multiplicity of samples and tests in measurement cuvettes is carried out on a common rotor or carousel, as is often the case for automatic analysis systems.
The invention has developed an apparatus which makes it possible to measure both the scattered light from a sample, which is produced at angles outside the axis of the incident light, and the light transmitted at angles around 0°.
Different narrowband or broadband light sources can be used to excite the material to be measured. These are guided on a common beam guidance arrangement to the reaction location. The pulsed driving of the light sources enables mutual disturbances or interference to be completely surpressed.
It is likewise an aim of the method described to carry out a validation of the bea
Dade Behring Marburg GmbH
Evans F. L.
Finnegan, Henderson Farabow, Garrett and Dunner L.L.P.
Geisel Kara
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