This worked example is a composite drawn from the rejection patterns that appear repeatedly in pre-analytical audits. The proportions illustrate the typical distribution rather than describing one laboratory's reported statistics, and the sequence of investigation is the part worth copying.
Rejections are expensive out of proportion to their number. Each one consumes a collection, a courier leg, an accessioning step and a repeat appointment, and the patient experience usually takes the worst of it.
Where the rejections actually originated
Splitting the rejected specimens by cause produced a familiar distribution: the larger share clustered in labelling and identification, a substantial minority in transport and packaging, and the remainder in collection timing and volume. Very little sat in the analytical phase itself, which is where most laboratories instinctively look first.
That distribution is the reason the fix belongs upstream. A change in the collection room or the transport route affects every rejection cause except the analytical one.
The three fixes, in order of effect
First, labelling at the bedside rather than at the collection tray. The change is procedural and costs nothing except a habit: label the tube in front of the patient, not after leaving the room. Rejections from mismatched or missing identifiers dropped first because the failure point was removed rather than detected.
Second, packaging standardised to one format per transport category. Two categories cover most shipments: bags rated to the pressure standard for Category B transport, and three-wall transport bags where absorbency and documentation separation are the requirement. Standardising removed the judgement call at the packing bench.
| Fix | What changed | Effect on rejections |
|---|---|---|
| Bedside labelling | Procedure and staff habit | Largest single reduction |
| One packaging format per category | Stock and packing bench layout | Reduced transport-related rejections |
| Rejection log with cause codes | Feedback loop to the collection site | Made the remaining causes visible and addressable |
| Temperature documentation | Shipper and logging practice | Reduced timing and temperature queries |
Third, a short rejection log with defined cause codes, fed back to the collection sites monthly. Once the collection sites could see their own numbers, the remaining causes became self-correcting.
Why packaging specifications matter more than they appear
Specimen packaging sits inside a transport regime, and in Canada that includes federal dangerous goods requirements for certain shipments. A bag that meets the pressure standard is not automatically the right bag for every shipment: the absorbent material, the secondary containment and the way documentation is kept separate all form part of the specification. Our explainer on where TDG applies to specimen collection in Canada covers the obligation, and the comparison of 95 kPa rated and three-wall transport bags explains which format suits which shipment.
What the laboratory would do differently
Two things. It would start the rejection log before changing anything, so the baseline was measured rather than estimated. And it would involve the collection sites in defining the cause codes, because codes invented in the laboratory did not match the categories the collection staff recognised in the field.
Our reference on specimen receipt and chain of custody sets out the SOP structure that sits behind a rejection log.
Two packaging formats cover most laboratory volumes: 95 kPa rated 6 x 9 inch 95 kPa specimen bags for routine Category B transport, and 6 x 9 three-wall transport bags where absorbency and documentation separation drive the choice.
Laboratories standardising packaging across collection sites can price the format on one order — request a bulk quote with the shipment categories and monthly volumes.
Ordering for a clinic, lab or care home? Wholesale and multi-site ordering covers case pricing and account setup, and the B2B wholesale collection lists the lines stocked for institutional buyers.
Related reading
- Does TDG Apply to Specimen Collection in Canada? What Clinics Must Actually Do
- 95 kPa Specimen Bags vs 3-Wall Transport Bags: Which Do You Need?
- Specimen Receipt and Processing SOP: Chain of Custody and Traceability
Frequently Asked Questions
What is the single largest cause of specimen rejection?
Identification failures — missing, incomplete or mismatched labelling. They are also the lowest-cost failures to fix, because the remedy is a change of habit rather than a purchase.
Does a rejection log need to be electronic?
No, but it needs consistent cause codes and a feedback path to the collection site. A spreadsheet with agreed codes does the job at small volume.
How often should packaging specifications be reviewed?
Whenever the transport route, the courier or the shipment category changes, and at least annually against the current regulatory requirement.
Can a laboratory refuse to accept a specimen?
Acceptance criteria are a laboratory policy question with a regulatory dimension. What matters is that the criteria are written, applied consistently, and communicated to the collection sites.
CliniEco Medical is a licensed medical device establishment (MDEL #35334).
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