Six Tubes, One Snowstorm, One Warfarin Dose

1. Citrate tube for PT/INR - REJECT. A 3.2% citrate tube must be filled to at least 90% of its draw volume. At three-quarters full the blood-to-citrate ratio falls far below 9:1, extra citrate binds calcium, and the INR is falsely prolonged. A spurious high INR in a warfarin patient can trigger a held dose or a vitamin K dose. Reject and request a redraw.

2. Bilirubin - REJECT. Bilirubin is photolabile and degrades within about an hour of ordinary room light exposure. Unprotected for 7.5 hours, the result would be falsely low and could delay recognition of rising bilirubin in a jaundiced neonate. Request a redraw wrapped in foil or amber plastic.

3. EDTA CBC - ACCEPT with a comment. Whole-blood EDTA samples are generally stable for cellular parameters for about 24 hours at room temperature. At 7.5 hours the CBC is reportable; note the collection time on the report and inspect the smear if any result looks atypical.

4. Urine culture - REJECT. Urine held at room temperature for 7.5 hours allows overgrowth of mixed flora and obscures the true pathogen, potentially producing a false-positive culture and unnecessary antibiotics. Beyond about 2 hours at room temperature, request a fresh clean-catch or a specimen refrigerated from the time of collection.

5. Lipid panel SST - ACCEPT with a comment. Total cholesterol, HDL, and calculated LDL are robust over this window. Triglycerides may drift upward at room temperature, so document the 7.5-hour delay.

6. Partially labeled SST - REJECT. A surname is not identification. Do not add identifiers after the fact; that is a mislabeling event, not a clerical fix. Reject, document, and request a redraw with two identifiers and the collection time.

Refuse: run the underfilled citrate tube and release the number. There is no interpretive comment that makes a falsely prolonged INR safe to act on for warfarin dosing, and 'the tube was short' does not travel with the result into the prescribing decision.

Options to offer, in order of preference:

1. Redraw at a site with STAT courier coverage or at the hospital outpatient lab tonight. A properly filled citrate tube drawn now and spun within the stability window gives a defensible result before the dose is due.
2. Point-of-care INR, if the practice or the hospital has a validated device and the patient can be seen, accepting that POC capillary INR carries its own bias and should not be used to titrate a large dose change without confirmation.
3. Dose on the last reliable INR and clinical judgment. Ask when the last acceptable INR was drawn and what it was. Many warfarin nomograms allow a dose based on a recent stable INR with a repeat the next day, and this is a clinical decision for the prescriber, not the laboratory.

What to say: 'The tube is underfilled, which falsely raises the INR. I cannot give you a number I can defend. I can have a redraw result to you by roughly 21:00 if the patient can get to the hospital lab, or you can dose from the last INR and recheck tomorrow.'

Document the rejection time, the reason, who was notified, what was offered, and what the practice decided. Offer to call the prescriber directly if the office manager is not transmitting the message accurately.

Root cause is systemic, not individual. Three collection sites feeding one afternoon courier with a single bag and one cold pack means collection-to-receipt time is governed by the courier schedule, not by specimen stability. A 7.5-hour transit in a snowstorm was predictable, and the tubes that arrived were mostly unsuitable because the system allowed unsuitable tubes to be collected and shipped.

Process changes:

1. Publish a stability table by tube type and analyte, posted at each draw station, with the maximum room-temperature window printed on it. Staff should be able to see that urine culture is a 2-hour room-temperature specimen while a lipid panel is not.
2. Split the courier runs by urgency. Give the practice a STAT channel (direct courier or hospital draw site) for INR, urine culture, and light-sensitive analytes, and reserve the routine run for stable chemistry.
3. Build rejection feedback into the loop. Send a weekly rejection log to the practice manager with tube type, reason, and collection time, and review it monthly. Track the rejection rate as a metric so improvement is visible.

Also add: a documented light-protection step (foil sleeve at the draw station, not improvised at the receiving lab), a labeling checklist at the point of collection, and a written escalation path so an office manager cannot pressure a bench tech into releasing a compromised result. File the whole review as a corrective action with an owner and a review date.