In my project, PCT is analyzed on two different platforms, COBAS 6000 and KRPTOR to evaluate the parameters of COBAS 6000.
The evaluation parameters are:
Linearity- Linearity testing is the assessment of useful analytical range of a laboratory method. The stating the upper and lower limits of the range are usually stated by the manufacturers’ as their reportable range of their methods. A linear response produced by the analytical method is generally assumed and the upper and lower limit is then reportable.

Analytical sensitivity- Analytical sensitivity is the evaluation of the lowest concentration of procalcitonin that can be measured. It is critical to have accurate information on the lower concentration limit to have an indication on the measuring range

Method comparison- Using linear regression and correlation, Method comparison is carried out to investigate the degree of association between two analytical methods. for this project, BRAHMS KRYTOR and COBAS 6000 PCT assays would be the analytical methods being compared. When the replacement of a current method with a new method is considered, Comparison of methods is often performed as it can determine if the new method has better operational qualities than the former one.

Interferences- The interference/limitations experiment is carried out to calculate the amount of interference caused by other materials that may be present in the samples being analyzed. The limitations of the procalcitonin assay must be well understood as interfering materials would deviate the result and thus reducing the accuracy. The concentration and type of interfering material also plays a part in the degree of deviation. Typical interferences include haemolysis samples, icteric samples and lipemia samples.
Imprecision- The imprecision experiment estimates the random error caused by varying daily operations of the method, such as the pippetting of samples, the reaction conditions that depend on timing, mixing, temperature, and heating. With automated systems, such as COBAS 6000, small variations may occur due to the lack of uniformity and the instability of instrument and reaction conditions.

There are two types of imprecision experiments. Within-run imprecision involves the testing of samples within a run (1 day) while between-run imprecision involves the testing of samples conducted over a longer period of twenty days. When samples are analyzed within a single analytical run, the "within-run" random error observed will generally be low because the results are affected only by varying factors in that single run as compared to an between run experiment conducted over a period of twenty days, which is expected to provide an even more realistic estimate of the variation that will be seen in patient samples over time

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