Hematoma and a Short Citrate Tube During an INR Draw
Friday afternoon a 68-year-old man with atrial fibrillation comes in for a PT/INR check ordered by his cardiologist. His medication list includes warfarin 5 mg daily with a dose adjustment two weeks ago, metoprolol, and omeprazole. He reports easy bruising. You select a 23-gauge butterfly needle and draw from the right antecubital fossa. Blood flows well, but as you withdraw the needle a 3 cm hematoma forms within seconds, and the patient says his fingers feel "pins and needles." You realize the light blue (citrate) tube was collected last, after the EDTA tube, and it is filled only to about half of the required volume.
1. What do you do in the first five minutes?
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Treat the patient first; the specimen problem comes second.
Immediate actions:
- Remove the needle and apply firm, direct pressure with gauze for at least 5–10 minutes - longer for a patient on warfarin. Do not bend the arm; bending hides bleeding and reduces effective pressure.
- Elevate the arm above heart level and apply a cold pack over the gauze.
- Assess distal to the site: radial pulse, capillary refill, color, warmth, sensation, and ability to move the fingers. The "pins and needles" may be transient nerve irritation or pressure from the hematoma; it must be tracked, not dismissed.
- Notify the provider and keep the patient seated and observed until symptoms resolve and bleeding is controlled.
Escalate if numbness persists, the hand becomes pale or cool, pain increases, or the hematoma expands: that suggests arterial involvement or compartment pressure and needs urgent provider assessment.
Document the site, needle gauge, onset, size, interventions, timestamps, and the patient's symptom course. An incident report is filed per policy and is not part of the medical record.
2. What is wrong with the specimen, and how do you correct it?
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Two separate errors make this citrate tube unusable.
Order of draw: citrate must be collected before EDTA. Drawing light blue after EDTA allows carryover of EDTA (a calcium chelator) into the citrate tube, which falsely prolongs clotting times.
Fill volume: citrate tubes must be filled to the indicated line to preserve the 9:1 blood-to-anticoagulant ratio. A half-filled tube has excess citrate, which binds calcium and yields a falsely prolonged PT/INR. On warfarin, a falsely high INR could trigger an inappropriate dose reduction, so this matters clinically.
Correction: discard this specimen and recollect from the opposite arm with a 21-gauge needle if the veins allow, or a butterfly with a discard tube drawn first to prime the tubing. Fill the citrate tube to the line, mix by gentle inversion 3–4 times, label, and send promptly. Note the recollection and reason on the requisition and tell the provider the INR will be delayed so dosing is not adjusted on a bad result.
3. How do you handle documentation, patient instructions, and the specimen delay?
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Chart: objective facts - vein site, needle gauge, tube types in collection order, hematoma size and time, pressure duration, distal neurovascular checks with times, provider notified, patient's reported symptoms and their resolution. Avoid speculation about fault.
Incident report: complete per policy, separately from the chart, describing what happened and what was done. It supports quality review and is not a place for blame.
Patient instructions: keep the arm uncomplicated - no heavy lifting or straining with that arm for the rest of the day, cold pack 15–20 minutes at a time, and watch for expanding swelling, cool or pale fingers, or numbness. Give a contact number and tell him whom to call. Confirm he has a ride if he feels unwell.
Follow-up: the recollected INR will be later than expected; confirm the result reaches the cardiologist before any dose change. Document the callback with the result once released, and flag the vein history in the chart so future draws use the other arm and a larger needle.