Every lot carries a unique identifier assigned during processing. That identifier is meant to stay attached to the product through storage, shipping, and receipt at the clinic, and from there to whatever record the clinic keeps when the product is used. Traceability depends on that chain being unbroken at every step, not just at the supplier's end.
On the clinic side, traceability means logging the lot number against the patient record at the time a product is used, alongside the date, quantity, and who administered it. This recordkeeping is what allows a specific lot to be identified quickly if a question about that lot arises later, rather than requiring a review of an entire shipment or order history.
Lot traceability works only as well as the records kept at each link in the chain. A clinic that discards lot numbers after receiving a shipment, or stores product without a system for recording which lot was used for which patient, breaks the chain even if the supplier's own documentation was complete.
Lot-level recordkeeping on the clinic side is what makes a supplier's documentation, such as a COA or donor eligibility summary, useful later, and clinics should have a system for it before product arrives, not after.