Planning SQC strategies and adapting QC frequency for patient risk

Reference change value and measurement uncertainty of CRP, ferritin, procalcitonin, troponin I and BNP tests in COVID-19 monitoring: how much change matters?

“…The ability to provide additional information about the characteristics of the measurement procedure along with the test results in laboratory reports provides valuable assistance to the correct interpretation of patient clinical status and the evaluation of response to treatment [15]. The allowable total error values (%) of CRP, ferritin, troponin, BNP, and procalcitonin measurement procedures are 56.6, 16.9, 27.91, 30, and 20.3, respectively [10,11,16]. In our study, we determined that the calculated CV a values of the CRP, ferritin, troponin, BNP, and procalcitonin measurement procedures were lower than the allowable total error values (Table 1).…”

“…Intra-individual coefficient of variation (CV i ) values of 34.1% and 12.8% were obtained for CRP and ferritin, respectively, from the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Biological Variation Database managed by the EFLM Biological Variation Working Group and the Biological Variation Database Task Group [9]. The CV i value of procalcitonin was 14% [10], and the CV i value of troponin I and BNP was 14.05% and 10%, respectively [11] (Table 1).…”

Integrating moving average control procedures into the risk-based quality control plan in small-volume medical laboratories

“…The Patient Risk Factor corresponding to the MaxE (Nuf) value was set in the calculator to 1. This ensured that the number of erroneous patient results would not exceed one if an analytical error occurred between two QC events ( 9 ). For each control material level, in addition to the calculated sigma metric value, the calculator gives a Patient-risk sigma value.…”

“…The calculation of this parameter is very complex and therefore impractical for routine use in laboratories (8). The practical information that laboratories actually need to establish QC frequency is the run size, i.e., the number of patient samples between two control measurements (9). The calculation has been simplified by designing a run size nomogram between two control measurements (10) and recently further facilitated due to the availability of an online run size calculator on the Westgard website (9).…”

“…The practical information that laboratories actually need to establish QC frequency is the run size, i.e., the number of patient samples between two control measurements (9). The calculation has been simplified by designing a run size nomogram between two control measurements (10) and recently further facilitated due to the availability of an online run size calculator on the Westgard website (9). In order to use this nomogram, as well as the calculator, it is necessary to know the Sigma-metric of a laboratory test.…”