06_Immunoturbidimetria e Nefelometria

7/27/2019 06_Immunoturbidimetria e Nefelometria

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Turbidimetria e nefelometria

Tecniche immunochimiche

quantitative per proteine


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104 to 1012 L/mol


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http://www.whfreeman.com/immunology/CH06/kuby06.htm
http://www.whfreeman.com/immunology/CH06/kuby06.htmhttp://www.whfreeman.com/immunology/CH06/kuby06.htm


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When a diluted antigen solution is mixed with a corresponding antibody, the reaction between the

antigen and the antibody results in the formation of immune complexes. The solution becomes turbid.

Turbidimetry is based on an optical detection system that measure the turbidity, the concentration of

very small particles suspended in a solution. A light beam (incoming light, yellow arrow) sent trough a

solution is scattered depending on the degree of turbidity. A photodetector mesures the reduction in the

intensity of the light beam (transmitted light, blue arrows).

Since the transmitted light represents a decreasing signal (the more turbid the solution, the more light

will be absorbed), one normally refers to the ABSORBANCE this being an increasing quantity in

relation to the antigen concentration.

TURBIDIMETRY


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TURBIDIMETRY, IMMUNOTURBIDIMETRY: to

measure plasmatic and urinary proteins.

A complete line of CE marked last

generation tests: monoreagents, with stability

over 18 months, mostly without sample

predilution, short testing time, easy to automate.

Kits are available in standard bottles as well as in

Hitachi compatible bottles or upon customer

need.

Controls and calibrators complete this very

special line.


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Nephelometry

Analytical methods which depend on the measurement of the

intensity of scattered light emanating from an illuminated volume of

an aerosol. The ratio of scattered intensity to illuminating intensity iscompared with a standard of known properties.

1990, 62, 2202

IUPAC Compendium of Chemical Terminology 2nd Edition (1997)


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Rayleigh scattering (named afterLord Rayleigh) is the scattering oflight by particles much smaller

than the wavelength of the light. It occurs when light travels in transparent solids and liquids, but is

most prominently seen in gases. Rayleigh scattering of sunlight from particles in the atmosphere is

one reason light from the sky is blue.

The amount of Rayleigh scattering that occurs to a beam of light is dependent upon the size of the

particles and the wavelength of the light; in particular, the scattering coefficient, and hence the

intensity of the scattered light, varies inversely with the fourth power of the wavelength, a relationknown as the Rayleigh law. Scattering from particles larger than about a tenth of the illuminating

wavelength is handled by Mie theory.

The intensity Iof light scattered by a single small particle from a beam of light of wavelength and

intensity I0 is given by:

where Ris the distance to the particle, is the scattering angle, n is the refractive index of the particle,

and d is the diameter of the particle.
http://en.wikipedia.org/wiki/Lord_Rayleighhttp://en.wikipedia.org/wiki/Scatteringhttp://en.wikipedia.org/wiki/Lighthttp://en.wikipedia.org/wiki/Wavelengthhttp://en.wikipedia.org/wiki/Diffuse_sky_radiationhttp://en.wikipedia.org/wiki/Bluehttp://en.wikipedia.org/w/index.php?title=Scattering_coefficient&action=edithttp://en.wikipedia.org/wiki/Mie_theoryhttp://en.wikipedia.org/wiki/Refractive_indexhttp://en.wikipedia.org/wiki/Refractive_indexhttp://en.wikipedia.org/wiki/Mie_theoryhttp://en.wikipedia.org/w/index.php?title=Scattering_coefficient&action=edithttp://en.wikipedia.org/wiki/Bluehttp://en.wikipedia.org/wiki/Diffuse_sky_radiationhttp://en.wikipedia.org/wiki/Wavelengthhttp://en.wikipedia.org/wiki/Lighthttp://en.wikipedia.org/wiki/Scatteringhttp://en.wikipedia.org/wiki/Lord_Rayleigh


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FilterTrak 660 Laser Nephelometer Optical Configuration


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The BN ProSpec, the system of choice for

customers performing routine and specialty Plasma

Protein assays in medium throughput laboratories in

more than 50 countries worldwide has achieved a

new milestone. Dade Behring is pleased to announce

the placement of the 1000th BN ProSpec system.

The customer centered development process of the

BN ProSpec; system contributed significantly to

such wide acceptance and has been recently

recognized with the achievement of the 2003

International Project Management Award (IPMA).

This process allows our customers to be involved in

the development of system features.

Antigen excess security through optimized reaction conditions and pre-reaction protocols

Broad continouosly extended assay menu

Calibration of various assays in parallel using multi-analyte standards

Excellent assay precision and recovery of controls

Flexible combination of various types of sample tubes on any one segment

Full barcode identification of samples, controls, standards and reagents

Fully automated sample processing including customized re-measurements

More than 60 assay protocols allow determinations in serum, plasma, urine and CSF

Patient-oriented sample processing

Refrigerated on-board storage of controls and reagents


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Clinical Chemistry and Laboratory Medicine

Volume 39, Issue 11 (2001)

Sren Blirup-Jensen

Protein Standardization III: Method Optimization. Basic Principles for Quantitative Determination ofHuman Serum Proteins on Automated Instruments Based on Turbidimetry or Nephelometry

Abstract

Quantitative protein determinations in routine laboratories are today most often carried out using

automated instruments. However, slight variations in the assay principle, in the programming of the

instrument or in the reagents may lead to different results. This has led to the prerequisite of method

optimization and standardization. The basic principles of turbidimetry and nephelometry are discussed.

The different reading principles are illustrated and investigated. Various problems are identified and asuggestion is made for an integrated, fast and convenient test system for the determination of a

number of different proteins on the same instrument.

An optimized test system for turbidimetry and nephelometry should comprise high-quality antibodies,

calibrators, controls, and buffers and a protocol with detailed parameter settings in order to program

the instrument correctly. A good user program takes full advantage of the optimal reading principles for

the different instruments. This implies - for all suitable instruments -sample preincubation followed byreal sample blanking, which automatically corrects for initial turbidity in the sample. Likewise it is

recommended to measure the reagent blank, which represents any turbidity caused by the antibody

itself. By correcting all signals with these two blank values the best possible signal is obtained for the

specific analyte. An optimized test system should preferably offer a wide measuring range combined

with a wide security range, which for the user means few re-runs and maximum security against

antigen excess. A non-linear calibration curve based on six standards is obtained using a suitable

mathematical fitting model, which normally is part of the instrument software.
http://www.degruyter.de/journals/cclm/cclm39_11.htmlhttp://www.degruyter.de/journals/cclm/cclm39_11.html

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06_Immunoturbidimetria e Nefelometria