Scandinavian journal of clinical and laboratory investigation
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Scand. J. Clin. Lab. Invest. · Jan 2004
Comparative StudyClinical evaluation of the measurement of serum procalcitonin: comparative study of procalcitonin and serum amyloid A protein in patients with high and low concentrations of serum C-reactive protein.
Levels of C-reactive protein (CRP) and serum amyloid A protein (SAA) in blood are increased as acute phase proteins in patients with inflammatory conditions. Most of the currently used inflammatory markers, such as erythrocyte sedimentation rate and CRP or SAA levels, are non-specific parameters. By contrast, procalcitonin (PCT) has been reported to be selectively induced by severe infection in systemic inflammatory response syndrome (SIRS) and also in sepsis or multiorgan dysfunction syndrome. ⋯ In patients with high levels of CRP, all patients with sepsis and severe bacterial infection showed a significantly increased PCT concentration of more than 1.0 microg/L and it was possible to differentiate between the patients with neoplastic disorders and those with other inflammatory diseases. In patients with low levels of CRP, the PCT concentration was less than 0.3 microg/L and an increased PCT level was not seen in patients with autoimmune disorders or viral and fungal infections. These results suggest that determining the serum PCT level may be useful in the differential diagnosis of severe infection.
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Scand. J. Clin. Lab. Invest. · Jan 2004
ReviewPrerequisites for establishing common reference intervals.
Establishment of common reference intervals for homogeneous populations within regions is based on the same basic principles as the IFCC recommendations for individual laboratories, but a few additional prerequisites are needed. Thus, the need for common standardization and traceability during production of the reference values and with the application of the common reference intervals in the laboratories becomes crucial. Furthermore, the external control system must be geared to the purpose, using matrix-correct control materials with concentration values traceable to the same reference methods, and validation of results according to analytical quality specifications designed for the use of common reference intervals. ⋯ Therefore, the strategy and the criteria must be thoroughly described. Arguments for establishing common reference intervals are not needed. On the contrary, lack of such common reference intervals should be explained.
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Scand. J. Clin. Lab. Invest. · Jan 2004
Comparative StudyBiosynthesis of 32P-labelled hydroxocobalamin and a study of its behaviour in rats.
Using Propionibacterium freudenreichii and 32P-ATP, batches of 32P-labelled cobalamin (Cbl) were biosynthesized with a maximum specific activity of 61 microCi/mg, i.e. about 100 times higher than previously reported. Pharmacological doses mixed with 57Co-Cbl were injected subcutaneously in the form of hydroxo-Cbl into rats subsequently killed 5-20 days later. The two labelled Cbls were distributed in approximately the same way, the highest concentration being found in kidney (typical for rats) and about one-fifth of that in liver. ⋯ In rats receiving the vitamin orally, the ratio was higher in liver than in kidney. All of our findings could be due to formation of a cobinamide-like compound lacking phosphorus. It is concluded that we have produced radiophosphorus-labelled Cbl that enables studies in vivo.
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Scand. J. Clin. Lab. Invest. · Jan 2004
Analytical quality goals derived from the total deviation from patients' homeostatic set points, with a margin for analytical errors.
The deviation of test results from patients' homeostatic set points in steady-state conditions may complicate interpretation of the results and the comparison of results with clinical decision limits. In this study the total deviation from the homeostatic set point is defined as the maximum absolute deviation for 95% of measurements, and we present analytical quality requirements that prevent analytical error from increasing this deviation to more than about 12% above the value caused by biology alone. ⋯ As a result, when the most common control rules are used, the analytical standard deviation may be up to 0.15 times the intra-individual standard deviation. Analytical improvements beyond these requirements have little impact on the interpretability of measurement results.
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Scand. J. Clin. Lab. Invest. · Jan 2004
Effect of analytical quality on establishing common reference intervals and their use.
In the Nordic Reference Interval Project (NORIP), reference intervals were established for 25 common clinical biochemical quantities. In the project, samples from more than 3000 reference individuals collected in the 102 participating laboratories from all five Nordic countries were analysed locally. In order to maintain a high level of analytical quality and to document this quality, a common calibrator/reference preparation (CAL) and a number of control samples were analysed together with the reference samples. ⋯ The analytical quality specifications (analytical goals) were based on specifications created directly for the purpose of sharing common reference intervals and only the bias criteria were used because bias is the dominating problem in transfer of reference intervals. These specifications were different for the evaluation of reference values to create common reference intervals and for the laboratories to use these common reference intervals (when established). An interesting outcome was that it was only for the biologically well-regulated quantities serum-sodium and serum-calcium that the selection of the best laboratories gave considerably narrower reference intervals.