Freezing Rain, Three Tubes With Conflicting Needs, and a One-Digit MRN
06:20 at a rural draw station. From a single venipuncture you collect a light-blue citrate tube for a PT/INR, an ammonia tube, and a bilirubin tube that you wrap in foil as soon as it is filled. The courier is scheduled for 08:15, but a freezing-rain warning says the van may be two hours late. You label each tube at the station from the printed barcode, checking name and MRN against the requisition as you go. At 07:50, while packing, you see that the bilirubin tube carries the correct name but an MRN that is one digit off from the requisition. The patient left at 07:30.
1. Can you fix the bilirubin label? Justify your answer and state what you do instead.
Read the worked answer
No. A mislabeled tube cannot be corrected - it must be discarded and, if possible, recollected.
- The label is the specimen's only claim about whose blood is inside. Once a tube carrying a wrong identifier has left your hand, no one downstream can verify what actually happened in that chair. Reprinting, striking through, or 'correcting' the MRN in the LIS converts a detectable error into an invisible one.
- Actions: quarantine the tube, do not send it, and record the nonconformance with the time, the tube type, and the nature of the mismatch.
- Contact the patient (she has left, so by phone per policy) to arrange a recollect, and notify the ordering provider that the bilirubin will be delayed.
- Review what caused the one-digit error - adjacent barcode on the sheet, fatigue at the end of a run - since the same slip could put the wrong patient's blood in a tube.
Reasoning: a delayed bilirubin is a scheduling problem; a bilirubin reported on the wrong patient can drive a wrong diagnosis and is indefensible in an audit.
2. Keep the two remaining tubes viable through a two-hour courier delay. What are the storage and transport conditions, and where do they conflict?
Read the worked answer
The three requirements cannot share one bag.
- Citrate (PT/INR): keep at room temperature, upright, in its rack. Do not ice or refrigerate it - cold activates factor VII and can falsely shorten clotting times. Testing should occur within about four hours of collection, so a two-hour delay already puts it near the limit.
- Ammonia: the most time-critical of the three. Keep it on ice (or in a cold pack slurry, not touching the tube directly) and deliver it as fast as possible; red cells continue to release ammonia at room temperature.
- Bilirubin: protect from light, keep at room temperature, and avoid hemolysis, which interferes with the assay.
- Practical plan: call the main lab, explain the weather delay, and ask for a stat run for the ammonia when it arrives. Pack the ammonia on ice in a separate bag from the citrate tube. Log the actual departure time.
Reasoning: packing everything on ice to 'keep it fresh' would invalidate the INR.
3. What do you document, and what would make you cancel a test outright rather than send it?
Read the worked answer
Document conditions and timing; cancel when stability is gone.
Record: the actual collection time, the planned and actual courier departure, the storage conditions for each tube, the bilirubin labeling event, and the recollect arrangement.
Cancel or recollect rather than send when:
- The ammonia arrives after its stability window has clearly elapsed. A falsely elevated ammonia invites treatment for hepatic encephalopathy that the patient does not have.
- The citrate tube is visibly underfilled or was chilled. The ratio or the cold artifact makes the INR meaningless, and a falsely shortened INR could lead to a missed dose of anticoagulant.
- Any tube is hemolyzed enough to invalidate the bilirubin.
Reasoning: an absent result prompts a redraw. A plausible-but-wrong result is acted on. When the chain of conditions cannot be guaranteed, the professionally honest output is 'not tested - recollect,' stated to the provider with the reason attached, plus an incident note so the same weather delay is planned for next time.