Analytical variation in metabolic profile testing
Summary Results are presented demonstrating quality control of the analytical procedures used during the application of metabolic profile tests to dairy herds over a period of 3 years. The significance of analytical variance is discussed in relation to the average population variance in dairy herds. It is concluded that analytical variance can be restricted to reasonable proportions providing that careful quality control is continuously employed.
Measurement of analytical precision in clinical chemistry.
Abstract Some factors affecting the precision of routine analytical methods have been investigated. The precision of urea, Na, K, Cl and CO 2 determinations with the Auto-Analyzer was better with aqueous solutions than with sera. The standard deviation increased, and the coefficient of variation decreased, with concentration in many methods. The precision of several methods was found to depend on the arrangement of control specimens and the duration of the test period. Standard deviations and mean values of control sera found on individual AutoAnalyzer plates often varied widely and independently. For several tests, the precision determined under standard conditions for either days, weeks or months varied considerably, particularly at higher concentrations. Significant changes in accuracy were shown to occur over short periods of time and these were reflected as a long term decrease in precision. Both the analytical precision and any change in accuracy should be taken into account when assessing the significance of alterations in measured values in patients.
The automated fluorometric determination of serum magnesium.
A modified flow diagram and a simplified reagent have been developed for the automated fluorometric determination of serum magnesium by the Hill procedure (1).