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R Masseyeff

Publications and source records attributed to R Masseyeff.

101 records · Page 6Linked to original sources
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[Evaluating an internal quality control procedure: application to multidimensional control].

Internal quality control keeps in constant evolution in the industrial world. Introducing in clinical chemistry new QC methods derived from the industrial practice raises the point of the means for their evaluation. The main evaluation criteria are discussed in this paper. The importance of ARL (average run length) as a key-criterion of the efficiency of a quality control procedure is stressed. These principles were applied to the multivariate approach of multilevel control with the Hotelling's T2. This method led to a better detection of random errors than the independently managed conventional Shewhart (Levey- Jennings) charts. Applied to systematic errors, both methods gave similar results with a certain lack of sensitivity. However the multivariate method can be sensitised using EWMA (exponentially weighted moving average), a method specific for improved bias detection. EWMA efficiency outperforms that of the older systems of rules. Moreover, in any kind of error, multivariate approach secures a well-defined false rejection rate, whereas this rate is dependant on unknown inter-level correlation coefficients in conventional QC.

Bias↗
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Occurrence of slowly sedimenting components with mu chain antigenicity in normal adult and cord serum.

The occurrence of trace amounts of slowly sedimenting components with mu chain antigenicity was investigated in 8 normal adult sera and 4 sera from cord blood of new-born infants. Separation of these components from 19S IgM was obtained by density gradient ultracentrifugation. The fractions were studied by radioimmunoassay. The results suggest that slowly sedimenting components with mu chain antigenicity occur in normal adult serum in amounts located in the mug/ml range. Several components sedimenting with various speeds were identified, although their sedimentation coefficients were not measured. This fact suggests that not only the already described 7S IgM monomer exists in normal blood but that other modes of association between mu and L chains or mu chains fragments also occur. Sera from cord blood showed patterns similar to that of adults.

Adsorption↗