We have developed a centrifugal analyzer with both fluorescence/light-scatter and conventional absorbance optics. The instrument is used in this investigation to study the formation of antigen-antibody complexes by light scattering and turbidimetric measurements, and to develop assays for human immunoglobulins G, A, and M. Concentrations are calculated from a nonlinear least-squares fit of cali...

In a cross-sectional study of over 3000 consecutive serum specimens the levels of rheumatoid factor (RF) measured by rate nephelometry (Beckman ICS II) were compared with values obtained by the more traditional methods of sheep cell agglutination (Rose-Waaler) and latex agglutination. Similar values for sensitivity and specificity were found for all three methods for rheumatoid arthritis, with ...

BACKGROUND AND OBJECTIVE Alpha-1 antitrypsin deficiency is an underdiagnosed condition in patients with chronic obstructive pulmonary disease. Diagnosis of this genetic condition is confirmed by genetic verification of pathology, but for screening purposes quantitative methods can be useful. The aim of our study was to evaluate sensitivity and specificity of quantitative methods for alpha-1 ant...

Serum protein deficiencies can be studied by qualitative, quantitative, and functional assays. Deficiencies of albumin, a ! anti trypsin (homozygous type ZZ), and IgG (especially subclass 1) can be detected easily by protein electrophoresis, whereas deficiencies of other proteins must be detected by specific immunochemical or functional assays. The diagnosis of congenital dysprotein­ emias invo...

Nephelometry is a laser based imaging technique, which uses the signal of light scattered off particles to provide information about the local number density of these particles. In densely seeded flows of practical interest, such as pulverised coal flames, particle loadings can become very high, to the point where the incident laser beam is severely attenuated. Therefore, measurements in flows ...

Absorption spectrophotometry is the measurement of an interaction between electromagnetic radiation and the molecules, or atoms, of a chemical substance. Techniques frequently employed in pharmaceutical analysis include UV, visible, IR, and atomic absorption spectroscopy. Spectrophotometric measurement in the visible region was formerly referred to as colorimetry; however, it is more precise to...

OBJECTIVE To evaluate the performance of the turbidimetric method of C-reactive protein (CRP) as a measure of low-grade inflammation in patients admitted with non-ST elevation acute coronary syndromes (ACS). METHODS Serum samples obtained at hospital arrival from 68 patients (66 11 years, 40 men), admitted with unstable angina or non-ST elevation acute myocardial infarction were used to measu...