Pretransfusion Sampling and Collection

This article covers the clinician's steps from sampling to bringing the unit to the bedside. The aim is a correctly identified sample, a complete request, timely collection and safe handling of the unit until it is given. Errors at this stage cause wrong blood in tube events, wasted units and delays.

Safety preparation.

• Collect the sample only from the patient in front of you, and label it at the bedside.

• Never label tubes before the sample is taken, and never label away from the patient.

• Use full name, date of birth and hospital number from the wristband, and the date, time and signature of the collector.

• Do not use a sample from an arm with an infusion.

Special groups.

• Emergency or unidentified patient: use the emergency identifiers and keep them for the whole episode.

• Neonates: use the infant's sample with a maternal sample, and record the details.

• Pregnant or recently transfused patients: samples are valid for a short window, usually 72 hours.

Sample. Usually 6 mL in EDTA for adults, and a small paediatric tube for infants, as the laboratory specifies.

Request form contents. Patient identifiers, ward, diagnosis, component and quantity, special requirements, indication, urgency, transfusion and pregnancy history, previous reactions, known antibodies, date and time needed, and the requesting clinician with contact number.

Collection requirements.

• A written or electronic collection slip identifying the patient and the units.

• A trained person authorised to collect, with a validated transport box when the unit will not be given immediately.

• A way to record the time the unit left controlled storage.

Sampling and request.

1. Identify the patient with the wristband and ask the patient to state name and date of birth if able.

2. Take the sample, and label it at the bedside.

3. Complete the request form accurately, then sign it.

4. Send the sample and the request to the blood bank promptly.

5. Agree the time of transfusion with the blood bank, so units are not collected before the patient is ready.

Collection of the unit.

1. Do not collect until the patient has intravenous access, the prescription is complete and a staff member is ready to start.

2. Collect one unit at a time, unless several are needed rapidly in haemorrhage.

3. At the blood bank, check the collection slip against the unit label: patient name, hospital number, date of birth, unit number, component and group.

4. Place red cells in a validated transport box if the transfusion will not start within the time limit set by the hospital.

5. Take the unit straight to the bedside and begin the bedside checks.

Time and temperature limits.

• Red cells: begin within 30 minutes of leaving controlled storage, or return to the blood bank within 30 minutes if the unit is unopened and has been kept as stated. Hospital policy varies, and the whole transfusion must be completed within 4 hours of leaving storage.

• Platelets: never refrigerate. Begin within 30 minutes of arrival.

• Plasma and cryoprecipitate: begin promptly after thawing, as the hospital time limit allows.

• Do not store blood in a ward refrigerator or a domestic refrigerator.

Complications of poor practice. Wrong blood in tube, delayed transfusion, discarded units, deterioration of the product from poor storage, and bacterial contamination of platelets.

Documentation. Time of sampling and person taking it, time of request, time of collection, who collected it, time of arrival at the bedside and time the transfusion started.

Quality assurance. Reject samples with incomplete labelling, and audit sample rejection rate, time to issue, units returned unused and wastage. Review incidents involving collection.

Referral and escalation. Blood bank medical staff for delays in compatible blood, rare requirements and recurrent rejection.