Chemistry: analytical and immunological testing – Composition for standardization – calibration – simulation,... – Blood serum or blood plasma standard or control
Reexamination Certificate
1998-04-03
2001-01-16
Wallenhorst, Maureen M. (Department: 1743)
Chemistry: analytical and immunological testing
Composition for standardization, calibration, simulation,...
Blood serum or blood plasma standard or control
C436S008000, C436S010000, C436S011000, C436S015000, C436S018000, C436S066000, C436S068000, C436S074000, C436S079000, C702S019000, C702S021000
Reexamination Certificate
active
06174728
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a control or calibration standard for use with instruments for optical measurement of the hemoglobin concentration in blood samples, and which includes scattering particles dispersed in an aqueous electrolyte solution.
DESCRIPTION OF THE PRIOR ART
For calibration and quality control in medical instrumentation systems, in particular for determination of the concentrations of different blood components, it is essential to provide stable control and calibration standards of good storage stability, for calibrating such systems prior to measuring and/or for to quality control at certain intervals.
Known hemoglobin standards are based on a suspension of red blood cells and platelets in an electrolytic solution, for example, which are used in determining the number of particles, hematocrit, and hemoglobin content. The standard is prepared using stabilized cell components of the blood. Such a standard is described in GB 2023287 A, for instance.
It is further known in the art to prepare hemoglobin standards from lysed erythrocytes by adding distilled water to them. The supernatant liquid is treated with a bacteriocidical agent and lyophilized. Before use, more water must be added to the standard in order to reconstitute the initial solution. Such a standard is described in GB 1129873 A, for example.
The disadvantage of these standards is their limited storage life and, in the instance of lyophilized standards, the expense and inconvenience of handling and potential mistakes involved therein.
In JP 1-301166 a standard liquid for calibration of a hemocytometer is disclosed which includes substantially spherical, first and second particles in aqueous electrolyte solution. The particles have sulfonic acid groups and/or sulfonate groups on the surface. The first particles have an average size of 1.9 to 3 &mgr;m, and preferably 2 to 2.9 &mgr;m, which corresponds to the size of human blood platelets, while the second particles have diameters of 4.5 to 5.5 &mgr;m and correspond to erythrocytes in size. Via the known number of particles per unit volume of the standard liquid, the particle counter may be calibrated with respect to the number of erythrocytes, blood platelets, etc., to be determined. The particles are obtained, for instance, by polymerization from a vinyl monomer with sulfonic acid groups, or by copolymerizing the monomer with other monomers. The electrolyte solution contains sodium chloride, potassium chloride, sodium phosphate, for example. The ratio of the numbers of first and second particles is 1:10-40. The standard liquid may be dyed to permit its use as a standard for measuring hemoglobin in blood.
In U.S. Pat. No. 4,945,062, finally, a liquid control standard for use in the quality assurance of blood analysis instrumentation systems is disclosed. The control liquid is suitable for systems determining pH, PCO
2
, and PO
2
in blood samples. The liquid is further used as a control standard for ion-selective electrodes (ISE), especially for measuring ionized calcium, total calcium, as well as the concentrations of Na, K and Li ions in blood samples. For measurement of the hemoglobin concentration (tHb) and several hemoglobin fractions, the autoclavable, stable, homogeneous standard contains absorbance means, preferably dyes from the group consisting of Acid Red Dye, Ponceau 3R Red Dye, Acid Yellow Dye, and Acid Blue Dye.
The above standards suffer from the disadvantage that the particles tend to sediment, such that the standards must be shaken or homogenized before use, or that some of the added dyes are not compatible with the sensitive layers of sensors and electrodes in the measuring devices and may thus obscure the measured values. Moreover, particle-sensitive measuring equipment will not respond to the dyes added.
SUMMARY OF THE INVENTION
It is an object of the present invention to propose a control or calibration standard for measuring instruments for optical determination of the hemoglobin concentration, which is suitable for use in systems with optical sensors, and which should be easy to handle and to prepare.
In the invention this object is achieved by providing that the scattering particles have a mean diameter of <0.6 &mgr;m, and preferably about 0.3 &mgr;m, and a volume concentration <1%, and preferably <0.3%. It has been found unexpectedly that the use of particles of a mean diameter of <0.6 &mgr;m, in particular in scattered-light geometries, will lead to reproducible measured values suitable for calibration and quality control in measuring instruments for optical determination of the hemoglobin concentration. Due to the small particle size, the scattering particles are kept in suspension more or less permanently by thermal molecular movement. It is not necessary in this context to modify the particles or their surfaces. The standard will thus remain homogeneous without any further measures and will be fully compatible with optical systems and sensors. Such scattering particles may also yield an optical signal which can be used for quality control or calibration of the oxygen saturation (SO
2
%).
Scattering particles having the required properties are manufactured and supplied in various diameters and materials, for example by PROLABO, 45300 Pithiviers, France; BANGS LABS, Fishers, IN 46038, U.S.A.; DYNO PARTICLES AS, N-2001 Lillestrom, Norway; or POLYSCIENCES INC., Warrington, Pa. 1876, U.S.A.
REFERENCES:
patent: 3977995 (1976-08-01), Louderback et al.
patent: 4001142 (1977-01-01), Turner
patent: 4151108 (1979-04-01), Sorensen et al.
patent: 4279775 (1981-07-01), Louderback et al.
patent: 4299728 (1981-11-01), Cormier et al.
patent: 4469792 (1984-09-01), Simmonds et al.
patent: 4945062 (1990-07-01), Chiang
patent: 5013666 (1991-05-01), Chiang
patent: 5185263 (1993-02-01), Kroneis et al.
patent: 5187100 (1993-02-01), Matzviger et al.
patent: 5227305 (1993-07-01), Manzoni et al.
patent: 5308767 (1994-05-01), Terashima
patent: 5422278 (1995-06-01), Herring
patent: 5547874 (1996-08-01), Terashima
patent: 5558985 (1996-09-01), Chiang et al.
patent: 5605837 (1997-02-01), Karimi et al.
patent: 0774655 (1997-05-01), None
patent: 1129873 (1968-10-01), None
patent: 2023287 (1979-12-01), None
patent: 2308444 (1997-06-01), None
patent: 1301166 (1989-01-01), None
Database WPI, Week 9003, Derwent Pub., AN 90-020045 of JP 01 301166A, dated Dec. 5, 1989.
Database WPI, week 8846, Derwent Pub., AN 88-328146 of JP 63 243879, dated Oct. 11, 1988.
Ben-David Daniel
Jobstl Ewald
Kroneis Herbert
Laughinghouse Charles L.
Tusa James K.
AVL Medical Instruments AG
Dykema Gossett PLLC
Wallenhorst Maureen M.
LandOfFree
Control or calibration standard for use with instruments for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Control or calibration standard for use with instruments for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Control or calibration standard for use with instruments for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2455233