ABSTRACT
We describe an immunoturbidimetric assay for estimating the concentration of apolipoproteins (apo) A-I and B in serum with a Cobas Bio centrifugal analyzer. Several analytical variables were studied: pH, temperature, wavelength, reaction time, sample pretreatment, antisera dilution, concentration of NaCl, phosphate buffer, and PEG 6000; a good optical response was obtained with small volumes of sample and antisera. Imprecision was low, with intrarun coefficient of variance (CV) from 1.1 to 2.8% and interrun CV from 1.8 to 3.2%. We demonstrated a good correlation between our method and radial immunodiffusion for apo A-I (r = 0.975) and apo B (r = 0.980). Reference values were calculated from a sample of 494 healthy subjects, and separate intervals for the ratio of apo A-I to apo B in gender and age subgroups were established.
Subject(s)
Apolipoproteins A/blood , Apolipoproteins B/blood , Nephelometry and Turbidimetry/methods , Adult , Aged , Aged, 80 and over , Analysis of Variance , Centrifugation , Female , Humans , Hydrogen-Ion Concentration , Male , Middle Aged , Phosphates/chemistry , Polyethylene Glycols/chemistry , Reference Values , Reproducibility of Results , Sodium Chloride/chemistry , TemperatureABSTRACT
Two new enzymoimmunoassays for FSH and LH adapted to the ES 600 analyzer (Boehringer Mannheim Diagnostics) were evaluated. The limit of detection was below 0.5 mIU/ml. Precision was excellent, the intra-assay coefficients of variation ranged from 1.2 to 2.2%, and the interassay variations from 2.0 to 2.8%. Both methods compared well with other commercial enzyme immunoassays, with correlation coefficients for FSH and LH of 0.988 and 0.974, respectively. There was no interference on the assays by the rheumatoid factor. The results of an external quality control assured the reliability of the measurements. Preliminary reference values were obtained.
Subject(s)
Follicle Stimulating Hormone/blood , Immunoenzyme Techniques , Luteinizing Hormone/blood , Adult , Child , Evaluation Studies as Topic , Female , Follicle Stimulating Hormone/analysis , Humans , Luteinizing Hormone/analysis , Male , Multicenter Studies as Topic , Reference Values , Rheumatoid Factor/analysisSubject(s)
Chorionic Gonadotropin/blood , Female , Humans , Immunoenzyme Techniques/standards , Male , Pregnancy , Quality ControlABSTRACT
An end point turbidimetric method for the determination of C3c and C4 in serum using a centrifugal analyzer (Cobas Bio) is described. Several analytical factors were evaluated -pH, temperature, PEG and antibody concentration. Wide variations of temperature and pH did not significantly affect the turbidimetric reaction. A 20 g/L PEG concentration and 25-fold antiserum dilution were found satisfactory for the analysis. Precision of the assay was good and comparison with a RID method yielded an r value of 0.97. The procedure is simple and reliable.
