The collectionDate on a HoldingTimeViolation is the reference point from which the holding-time clock started running. Piper calculates holdingDays as the difference between this date and the analysisDate. Reviewing the collectionDate together with analysisDate lets you immediately see the timeline of the problem — for example, if a sample was collected on the 1st and analyzed on the 20th for an analyte with a 14-day limit, the violation is clear and the overByDays value of 6 is easily verified.
Technical section
Data model, API, and internals — visible to developers.