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C Signorini

Publications and source records attributed to C Signorini.

At least 37 records · Page 2Linked to original sources
PubMed1991

Assessment of qualitative tests.

For qualitative (2-class) tests, which provide binary (yes/no) information, the correctness of specimen classification remains the most important criterion for performance evaluation. However, a more informative picture emerges from the relationship between percentage of positive results and analyte concentration, which allows some inherent test characteristics to be derived (the positive/negative discrimination concentration and the "grey zone" around it). The information content of evaluation approaches is decidedly improved by the availability of numerical results (counts per minute, absorbance) in most situations of clinical interest. The concentration/response functions underlying the quality of individual tests may thus be derived and compared, and laboratory staff given a more objective criterion to judge individual performance. Examples are drawn from the authors' experience in running external quality assessment programs for tests for infectivity markers.

Blood Chemical Analysis↗
PubMed1991

External quality assessment of assays for hormones and tumor markers in Italian laboratories.

External quality assessment (EQA) programs run by CNR/Tecnostandard for immunoassays of hormones and tumor markers, started in 1980, presently include as many as 20 analytes; about 300 laboratories are involved in these programs. For all immunoassays submitted to the EQA, the inspection of cumulative results allows the current situation to be documented for total variability and its within-kit and between-kit components (the former accounting for the reproducibility and robustness of the kits and the latter for their systematic differences of estimation). For 13 assays subjected to EQA for longer, the variability trends over time are depicted, and single factors affecting the overall quality of particular assays are identified. Among these, experimental simplification of kit structure, alignment of calibrators with an acknowledged reference material, and adoption of monoclonal-antibody based two-sites assays can be mentioned. On the contrary, neither automation of the procedures nor (more expectedly) increasing use of nonisotopic techniques has proved effective in significantly improving the analytical quality.

Biomarkers, Tumor↗
PubMed1991

Immunoassay external quality assessment in Italy: HBsAg and anti-HBs tests.

The mode of operation of the CNR/Tecnostandard external quality assessment scheme for HBsAg and anti-HBs assays is outlined, and the relevant results reported. Emphasis is given to the retrospective evaluation of data in an attempt to derive a picture of the state of the art in Italian laboratories. The approaches followed for this evaluation include analysis of the rate of correct results and inspection of the relationships between analyte concentration and either the percentage of positive classifications of samples or the numerical test responses. Information is given on the "average" performance of individual kits as actually used in participants' laboratories.

Evaluation Studies as Topic↗
PubMed1990

Iron release and erythrocyte damage in allyl alcohol intoxication in mice.

Allyl alcohol administration in a toxic dose (1.5 mmol/kg) to starved mice causes the development of hemolysis in nearly 50% of the animals. Malonic dialdehyde (MDA) appears in plasma of the animals showing hemolysis. The treatment of mice with desferrioxamine after allyl alcohol intoxication completely prevents lipid peroxidation and hemolysis, suggesting the involvement of iron in the allyl alcohol-induced erythrocyte damage. Erythrocytes obtained from intoxicated mice before the development of hemolysis show, upon incubation, release of iron, lipid peroxidation and lysis. Studies carried out with reconstituted systems of erythrocyte lysates, containing ghosts and different fractions of erythrocyte cytosol and incubated in the presence of acrolein (the major metabolite of allyl alcohol), strongly suggest that iron is released from hemoglobin. This iron appears to promote lipid peroxidation which is accompanied by erythrocyte lysis. Thus, the allyl alcohol-induced hemolysis appears to be a model for iron delocalization from iron stores.

1-Propanol↗
PubMed1985

Evaluation of valproic acid fluoroimmunoassay and comparison with a gas liquid chromatographic method.

A method for monitoring valproic acid in serum with a fluoroimmunoassay is described. The evaluation was performed with run-to-run and within-run reproducibility, dilution, and recovery tests. The interferences of hemoglobin, bilirubin, and triglycerides were checked, and a comparison with a gas liquid chromatographic method was also performed. The between-run and within-run coefficients of variation were less than 5.2 and 2.6%, respectively. The method gave satisfactory results in dilution tests and a high correlation with a gas liquid chromatographic method (r = 0.98). The percentage of recovery was greater than 97%. No interference from hemolysis, bilirubin, or triglycerides was observed. The accuracy and simplicity of this method make it suitable for routine laboratory use.

Bilirubin↗
PubMed1984

Plasma catecholamines assay: comparison between fluorimetric and radioenzymatic methods.

Plasma catecholamines were simultaneously measured in duplicate plasma samples by the fluorimetric method of Renzini et al. (1970) Clin. Chim. Acta 39, 587-594) and by the radioenzymatic method of Da Prada & Zurcher ((1976) Life Sci. 19, 1161-1174). The correlation of noradrenaline and adrenaline plasma concentrations determined by the two methods were, respectively, r = 0.95 (p less than 0.001) and r = 0.75 (p less than 0.01). The fluorimetric method was less sensitive, but more economical and less time-consuming than the radioenzymatic method. The fluorimetric method is still of value for measuring plasma catecholamines in man.

Catecholamines↗