Blood Component Prescription

A blood component prescription is a medication order with the same legal and safety weight as a drug order. An incomplete prescription is a leading cause of wrong product, wrong volume, wrong rate and wrong patient errors. Every transfusion must be prescribed by an authorised clinician, with the indication and the clinical target written, before the blood bank issues any unit.

Safety preparation.

• Confirm that transfusion is the right treatment and that alternatives were considered.

• Confirm consent and document it.

• Check the patient's current weight, haemoglobin, platelet count and coagulation as relevant.

• Check allergies, previous reactions, antibody history, pregnancy status and current drugs.

Special groups.

• Children and neonates: prescribe in mL/kg with the weight stated, and cap at the adult dose.

• Patients at risk of overload: state the rate and the monitoring.

• Women of childbearing potential: state RhD requirements.

Mandatory elements of the prescription.

1. Patient full name, date of birth and unique hospital number, matching the wristband.

2. Weight for children and neonates, and for dose calculations by weight.

3. Component name (red cells, platelets, plasma, cryoprecipitate, whole blood) and any special requirement (irradiated, cytomegalovirus safe, washed, antigen negative, neonatal grade).

4. Quantity: number of units for adults, or volume in mL (and mL/kg) for children.

5. Rate or duration for each unit.

6. Indication and target, for example haemoglobin under 7 g/dL with symptoms, platelets under 10 x 10⁹/L for prophylaxis, or active bleeding.

7. Urgency: emergency (minutes), urgent (within hours) or routine.

8. Observation frequency, if different from the usual.

9. Any ancillary medicine, only when specifically indicated, such as a diuretic in overload risk, written as a separate drug order.

10. Date, time, prescriber name, signature and contact number.

Equipment. The hospital's transfusion prescription chart or electronic order, a transfusion request form, and the current laboratory results.

Step by step.

1. Check the indication against the thresholds and conditions for the patient. Do not rely on a laboratory number alone.

2. Choose the component that treats the defect.

3. Select the quantity. In stable non-bleeding adults prescribe one unit at a time, with reassessment before the next. In bleeding patients prescribe as the response requires, with the blood bank informed.

4. Specify special requirements and the urgency.

5. Write the rate, for example: one unit of red cells over 3 hours, first 15 minutes slowly. For patients at risk of overload, write about 1 mL/kg/hour.

6. Write the reassessment: haemoglobin about 1 hour after completion, and clinical review.

7. Do not add premedication by habit. Antihistamines, steroids and antipyretics do not reliably prevent reactions, and they may mask early signs. Prescribe them only for a patient with documented recurrent reactions.

8. Sign, and send the request to the blood bank.

Examples of complete wording.

• Adult: red cells, one unit, irradiated, for symptomatic anaemia with haemoglobin 6.4 g/dL, over 3 hours, reassess haemoglobin 1 hour after completion.

• Child 18 kg: red cells 10 mL/kg (180 mL) over 3 hours, for malarial anaemia with haemoglobin 3.8 g/dL, reassess after completion.

• Plasma: 12 mL/kg (about 3 units in a 70 kg adult) for bleeding with prolonged prothrombin time, over 1 hour, recheck coagulation 30 minutes after.

Verbal and telephone orders. Avoid them. In an emergency, a verbal order is documented immediately in writing with the name of the prescriber, and countersigned.

Common prescribing errors.

• Missing indication or target, so units continue after the target is reached.

• Ambiguous quantity, such as "2 units" for a child, or "2 bags" for platelets.

• Mixing mL and units.

• Missing special requirement.

• Missing rate or time limit.

• Wrong patient or wrong date.

• Prescribing an adult dose for a child.

• Routine premedication.

Documentation. Retain the prescription in the record, with the indication, consent, rate, administration times and unit numbers.

Quality assurance. Audit the proportion of prescriptions with indication, special requirements and rate, and review incidents. Include prescription review in transfusion committee audits.

Referral and escalation. Transfusion specialist or blood bank medical staff for unusual requirements, large volumes and contested indications.