In-vitro diagnostic platforms are sold as instruments and used as subscriptions. The analyser is a capital line in a budget; the reagents, calibrators and controls are an operational line that never stops. A laboratory that has an analyser and no reagents has an expensive bench.
Most of what goes wrong in that supply line is temperature, and it goes wrong in four identifiable places.
1. The gap at origin
Product comes out of a controlled store and waits for collection. If the collection window slips and the pallet is standing on a loading dock, the excursion has already happened before the first shipping document exists.
The fix is procedural, not technical: the data logger is activated in the cold store, not in the vehicle, and its record starts before the product leaves controlled conditions.
2. The transfer between legs
Air freight of temperature-controlled goods is a series of handovers — forwarder, airline, ground handler, customs, forwarder again. Every handover is a place where a shipment can sit on an apron. Direct routings cost more and are worth it; a shipment that transits is a shipment with an extra opportunity to stand still somewhere hot.
3. Customs hold
This is the big one, and it is a documentation problem wearing a temperature costume. A consignment held for a paperwork query sits in whatever conditions the port provides. Hours are survivable in a properly qualified shipper; days are not.
The prevention is entirely upstream: registration current, certificate matching the manifest, invoice describing the goods in the terms the tariff uses, and the import permission in place before the goods leave origin — not while they are in the air.
4. The last mile
Cleared, and then delivered by a general courier in an unrefrigerated van, to a laboratory goods-in desk that is closed. This step is often the least controlled of the whole journey and it is the one entirely inside your own country.
A consignment held for a paperwork query sits in whatever conditions the port provides.
What the record has to show
For an accredited laboratory, the temperature record is part of the evidence that a result is valid. It should show:
- A continuous trace from the origin cold store to the receiving refrigerator, with no unexplained gaps.
- The specified storage range for the product, and every excursion above or below it with its duration.
- The logger's calibration certificate, in date.
- A documented decision on any excursion — accepted against the manufacturer's stability data, or rejected — signed by someone with the authority to make it.
That last point is the one most often missing. An excursion is not automatically a failure: manufacturers publish stability data precisely so that a short deviation can be assessed rather than guessed at. But the assessment has to exist, in writing, before the reagent is used — not reconstructed afterwards because a result was queried.
Buying the supply line, not the instrument
When you evaluate an IVD platform, evaluate the reagent line with the same seriousness: lead time, minimum order, shelf life on arrival, what happens to your throughput if a shipment is held, and whether a second routing exists. An analyser with excellent specifications and a single fragile supply lane is a worse purchase than a good analyser with two ways in.