Nephelometric assay

Nephelometric assay for chloride ions with AgNOs under weakly HN03-acidic conditions. 

Estimated from poster data presented in Rapid screening of aqueous solubility by a nephelometric assay ,... 

Nephelometric assay may be employed for the determination of sulphate (S042-) and phosphate (P 04 ) ions quite efficiently. These two estimations shall be discussed below in an elaborated manner ... 

Baldo-Enzi (Bl) compared the results of five different commercial immunoassays (a two-site RIA, an endpoint nephelometric assay, and three different ELlSAs) for freshly drawn serum and for plasminogen-free fractions (obtained by one-step ultracentrifugation). He observed a variable influence of plasminogen on the results of the Lp(a) determination and found no comparability between the five types of assays. This was partly due to lack of standardization. The different assays were more comparable when the plasminogen-free fraction was used. 

G18. Gillery, P., Arthuis, P., Cuperlier, C., and Circaud, R., Rate nephelometric assay of serum lipoprotein(a). Clin. Chem. (Winston-Salem. NC) 39, 503-508 (1993). 

A number of immunochemical techniques have been used to quantify analytes of clinical interest. They include radial diffusion (RID) and electroimmunoassays, turbidimetric and nephelometric assays, and labeled immunochemical assays. 

Grange J, Roch AM, Quash GA. Nephelometric assay of antigens and antibodies with latex particles. J Immunol Methods 1977 18 365-75. 

Nephelometric and turbidimetric methods (see Chapter 3) are performed on most current automated analytical systems, although most nephelometric assays are performed on dedicated instruments. RID requires no instrumentation other than pipettes, although some type of illuminated plate reader is advantageous. RIA requires radiation scintillation counters and an automated pipetting station. 

Non immunochemical Turbidimetric and Nephelometric Methods. Precipitation of protein for turbidimetric or nephelometric assays is achieved with sulfosahcylic acid alone, or with sulfosahcyfic acid in combination with sodium sulfate or trichloroacetic acid (TCA), or with TCA alone. Precipitation methods for total protein assay depend on formation of a fine precipitate of uniform, insoluble protein particles, which scatter incident light in suspension. 

The use of CRP for these purposes requires the use of hsCPR assays having detection limits less than 0.3 mg/L. " A number of automated immunoturbidimetric and inrnmno-nephelometric assays are commercially available and capable of sensitive and precise measurements at low concentrations of CRP. The analytical performance of nine of these assays has been evaluated. ... 

Chirtel, S. J., P. J. Coutlakis, L. L. Chambers, and M. R. Lakshman. 1989. A novel use of endpoint nephelometry to standardize the rate nephelometric assay of human and rat plasma apoprotein A. Journal of Laboratory and Clinical Medicine 113 632-641. 

Estimated from poster data. Presented in Rapid screening of aqueous solubility by a nephelometric assay, J. R. HiU, C. M. Curran, N. S. Dow, K. HaUoran, V. Ramachandran, K. G. Rose, D. J. Shelby, D. A. Hartman, Ricerca Ltd., AAPS... 

Turbidimetric and nephelometric assay Nephelo-metry and turbidimetry, because of their speed and ease of use, are most widely used. These techniques can be used either by measuring the amount of Ag-Ab complex formation (endpoint methods) or by measuring the rate of complex formation (kinetic methods). The kinetic methods are more rapid because measurements are accomplished within 20 s, and are more precise because sample blanks are not necessary. Kinetic assays are, however, somewhat less sensitive because low-affinity antibodies do not have time to react. The occurrence of Ag-Ab formation is related to the amount of light scattering and is used as the basis for antigen quantification. This approach has been accompanied by the development of... 

Sarobe, J., Miraballes, 1., Molina, J.A., Forcada, F., and Hidalgo-Alvarez, R. 1996. Nephelometric assay of IgG chemically bound to chloromethyl styrene beads. Polym. Adv. Technol. 7 749-53. 

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