Automated Immunonephelometric Assay for Human Alpha-1-Microglobulin

A method is described for establishing the optimal conditions for an immunonephelometric protein assay. This method has been derived for use on the Hyland PDQ (Travenol Laboratories, Thetford, UK) and Kallestad (Kallestad Laboratories Inc, Chaska, Mn, USA) nephelometers. We have also found it applicable to the Behring nephelometer (Hoechst, London, UK). Using this approach, it is possible to establish an assay on these instruments for any serum protein with a concentration above about 10 mg/l for which a suitable antiserum is available. The method has also proved suitable for developing methods for proteins in urine, CSF, saliva, and amniotic fluid. Proteins in urine may be measured at concentrations as low as 1 mg/l.

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Determination of α1-Acid Glycoprotein in Human Cerebrospinal Fluid by an Immunonephelometric Assay

Protides of the Biological Fluids ◽

10.1016/b978-0-08-029815-3.50058-1 ◽

1983 ◽

pp. 239-242

Author(s):

T.O. KLEINE ◽

B. MERTEN

Keyword(s):

Cerebrospinal Fluid ◽

Acid Glycoprotein ◽

Human Cerebrospinal Fluid ◽

Immunonephelometric Assay

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Manual Immunonephelometric Assay of Proteins, with Use of Polymer Enhancement

Clinical Chemistry ◽

10.1093/clinchem/20.9.1181 ◽

1974 ◽

Vol 20 (9) ◽

pp. 1181-1186 ◽

Cited By ~ 48

Author(s):

Jorge Lizana ◽

Kristoffer Hellsing

Keyword(s):

Detection Limit ◽

Urinary Albumin ◽

Optimal Time ◽

Immunological Reaction ◽

Reaction Conditions ◽

Enhancing Effect ◽

Lower Detection Limit ◽

Small Series ◽

Lower Detection ◽

Immunonephelometric Assay

Abstract A manual immunonephelometric method for proteins has been developed by using an ordinary fluorometer as a nephelometer. By applying the enhancing effect of polyethylene glycol (av mol wt, 6000) on the immunological reaction, albumin and fibrinogen were quantitated after a 10-min reaction time. Under the present conditions the sensitivity was increased and thus antiserum consumption was decreased. The reaction conditions were carefully studied with respect to optimal time and concentration of the reactants. The precision of the method was 2.6-3.6% (CV). The lower detection limit in the albumin-antialbumin system was 0.1 mg/liter. Comparative studies showed a correlation coefficient of 0.991 with an automated immunonephelometric method for urinary albumin, and of 0.908 with a thrombin clottable method for plasma fibrinogen. We especially suggest use of this manual immunonephelometric method where small series of samples are to be analyzed.

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Standardized automated assay for functional alpha 1-antitrypsin.

Clinical Chemistry ◽

10.1093/clinchem/30.11.1857 ◽

1984 ◽

Vol 30 (11) ◽

pp. 1857-1860 ◽

Cited By ~ 4

Author(s):

R E Mullins ◽

R L Miller ◽

R L Hunter ◽

B Bennett

Keyword(s):

Sample Size ◽

Active Site ◽

Functional Activity ◽

Active Sites ◽

Minimum Sample Size ◽

Automated Assay ◽

Minimum Sample ◽

Alpha 1 Antitrypsin ◽

Enzymic Assay ◽

Immunonephelometric Assay

Abstract We describe an enzymic assay for the functional activity of alpha 1-antitrypsin, in which tosyl-Gly-Pro-Lys-p-nitroanilide acetate (Chromozym PL) is the trypsin substrate. For the indicating reaction, the concentration of substrate is about double the Km of its reaction with trypsin. This assay is an improvement over reactions involving N-alpha-benzoyl-DL-arginine p-nitroanilide as substrate, the solubility of which in water is less than the Km of its reaction with trypsin. The assay is standardized in terms of active sites of trypsin inhibited per liter of serum, with p-nitrophenyl-p'-guanidinobenzoate as the active site titrant. The results agreed well with those by an immunonephelometric assay for alpha 1-antitrypsin (r = 0.953). The within-run and run-to-run precision was approximately 3%. The results of the assay varied linearly with alpha 1-antitrypsin concentration from 0 to 60 mumol/L of serum. The minimum sample size was 50 microL, and analysis of 24 samples took less than 20 min.

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Development and Multicenter Evaluation of the N Latex CDT Direct Immunonephelometric Assay for Serum Carbohydrate-Deficient Transferrin

Clinical Chemistry ◽

10.1373/clinchem.2006.084459 ◽

2007 ◽

Vol 53 (6) ◽

pp. 1115-1121 ◽

Cited By ~ 58

Author(s):

Joris R Delanghe ◽

Anders Helander ◽

Jos PM Wielders ◽

J Maurits Pekelharing ◽

Heinz J Roth ◽

...

Keyword(s):

Alcohol Abuse ◽

Genetic Variants ◽

Reference Method ◽

Sample Treatment ◽

Serum Samples ◽

Column Separation ◽

Direct Immunoassay ◽

Carbohydrate Deficient Transferrin ◽

Healthy Control ◽

Immunonephelometric Assay

Abstract Background: Carbohydrate-deficient transferrin (CDT) is a promising biomarker of alcohol abuse. We describe the development and multicenter evaluation of N Latex CDT (Dade Behring), an automated, particle-enhanced, homogeneous immunonephelometric assay for directly determining CDT. Methods: N Latex CDT uses a monoclonal antibody that recognizes the structure of transferrin glycoforms lacking 1 or 2 complete N-glycans [i.e., disialo-, monosialo-, and asialotransferrins (CDT glycoforms)] in combination with a simultaneous assay for total transferrin. The Dade Behring BN II™ and BN ProSpec® systems automatically calculate the CDT value as a percentage of total transferrin (%CDT). No preanalytical sample treatment is used. Results: Total imprecision values for serum pools containing 1.8%–8.7% CDT were 3.4%–10.4% (mean, 6.8%). The mean (SD) %CDT for 561 serum samples from healthy control individuals was 1.76% (0.27%; range, 1.01%–2.85%). No marked sex or age differences were noted. The 97.5th percentile was at 2.35%. Transferrin genetic variants did not interfere with measurements. High transferrin concentrations did not falsely increase %CDT values, but increased %CDT values were noted for some samples with transferrin concentrations <1.1 g/L. N Latex CDT results correlated with those of a commercial CDT immunoassay involving column separation (r2 = 0.862) and an HPLC candidate reference method (r2 = 0.978). Conclusion: N Latex CDT is the first direct immunoassay for quantifying %CDT in serum. The specificity of N Latex CDT for identifying alcohol abuse may be higher than for immunoassays that use column separation, because transferrin genetic variants do not interfere with measurements.

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