The response procedure
01Hold: Quarantine the product — don't discard it
An excursion is not automatically spoiled product. Move the affected lot to a known-good condition or mark it on hold so it cannot ship while the assessment is pending.
The hold itself should be recorded: what lot, how much, when the hold started.
02Record: Capture the facts while they are fresh
Start time, end time, worst value reached, cumulative time out of band, the asset, the product and lot affected, and the suspected cause (door left open, power loss, compressor failure, defrost fault, delivery left on a dock). A contemporaneous record is worth more than a reconstruction a week later — data-integrity expectations (the ALCOA+ principles: attributable, legible, contemporaneous, original, accurate) apply to deviation records exactly as they do to the readings themselves.
03Assess: Compare exposure to what the product can tolerate
The question is not 'did it leave the band' but 'did the product see conditions outside its stability profile'. USP <1079.1> frames this as a risk-based excursion assessment: how far out, for how long, and what the product's labelled storage and stability data say it can bear. For excursions that repeat or creep, mean kinetic temperature (MKT, USP <1079>) gives a single equivalent-temperature figure for the whole period rather than a pile of isolated peaks. Freeze-sensitive products have meaningful lower bounds too — colder is not always safer.
04Disposition: Decide, document, and sign
The outcome — release, release with a shortened expiry, rework, or reject — must be a documented decision with a rationale and an accountable person, not a verbal call on the floor. For biologics, FDA 21 CFR 600.14 expects written temperature-control procedures with documented excursions and their dispositions; EU Good Distribution Practice treats deviation handling and product disposition as core records. The disposition record is what an inspector reads first.
05Fix: Corrective and preventive action
One excursion is an event; a pattern is a system failure. Trend the events by asset, shift, cause and time of day before deciding what to fix: a recurring overnight warm-up points at defrost termination or door seals, a spike every delivery points at dock procedure, a slow drift points at a failing compressor or a sensor that needs recalibration. Record the action taken and verify later that it worked — closing the CAPA without verification is the finding an auditor is looking for.
What is mean kinetic temperature (MKT)?
Not every warm reading is an excursion
Defrost cycles, door openings during picking or delivery, and sensor placement near the coil all produce legitimate short warm readings that are part of normal operation — a cold room that never shows a door-open spike is usually a sensor that is not measuring the room. The practical test is dwell time and product temperature, not the single worst reading: a few minutes a degree warm during a delivery is a different event from hours of drift overnight. Treating every blip as an event buries the real excursions in noise, and an alarm nobody trusts is worse than no alarm.
What the excursion file should contain
- The band the asset is required to hold, and where it is registered.
- Start and end timestamps, worst value, cumulative time out of band.
- The readings around the event — the trend, not just the peak.
- Product and lot affected, and the hold placed on it.
- The assessment: exposure versus stability or labelled storage conditions.
- The disposition decision, rationale, and who made it.
- Corrective action and later verification that it worked.
How Cryovo produces this
Upload the logfile CSV. Cryovo registers each asset's band and keeps the band, start, duration, worst value and recovery on every event — so the excursion file assembles itself, complete and audit-ready, while the facts are fresh, and the trend is attached to the record instead of reconstructed later.
General information, not legal or compliance advice for your jurisdiction. Disposition decisions for regulated product belong to your qualified person. New to the vocabulary? See the Help page and the glossary.