Beschreibung:
<jats:sec>
<jats:title>Context.—</jats:title>
<jats:p>Delta checks are a powerful technique for monitoring clinical assays in many disciplines but have not been routinely used in molecular testing.</jats:p>
</jats:sec>
<jats:sec>
<jats:title>Objective.—</jats:title>
<jats:p>To determine if the biologically determined kinetics of BCR-ABL1's rise and fall could allow the development of a delta check in BCR-ABL1 testing.</jats:p>
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<jats:sec>
<jats:title>Design.—</jats:title>
<jats:p>Nine years of BCR-ABL1 p210 results were evaluated, and patients with 3 or more results were selected for inclusion. The kinetics of these percentages of international standard values were plotted against time along with the median and the 90th and 95th percentile lines. A Monte Carlo simulation of a batch mix-up was performed for 6 months of data to determine the efficacy of the proposed cutoff.</jats:p>
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<jats:sec>
<jats:title>Results.—</jats:title>
<jats:p>The median kinetics showed a 1-log drop of the percentage of international standard in 90 days, with less than 5% of cases showing faster than a 2-log drop in 90 days, and less than 2.5% showing a faster than 3-log drop in 90 days (extrapolated to 1 log in 30 days). The Monte Carlo simulation of a batch mix-up showed that an average batch mix-up of 23 samples could routinely be flagged by this cutoff, albeit with wide variance.</jats:p>
</jats:sec>
<jats:sec>
<jats:title>Conclusions.—</jats:title>
<jats:p>These results suggest that using a drop in the percentage of international standard of greater than 1 log in 30 days can be a useful trigger in implementing a delta-check system for this molecular test.</jats:p>
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