The Clinical Transfusion Process: The Hospital Blood Bank

Role of the hospital blood bank

Quality in transfusion practice must apply to the hospital blood bank or equivalent, because it plays a vital role in ensuring that the correct blood component is supplied for the patient.

The laboratory aspect of the transfusion process is carried out in different ways across the countries of the EU. In some settings a local hospital blood bank manages the blood component inventory and the clinical blood transfusion laboratory services. Elsewhere, the blood establishment provides compatible blood directly to hospitals.

EU Directives require that hospital blood banks implement a quality management system. To maintain a high level of performance in the laboratory, it is essential to monitor the functioning of reagents, equipment, techniques and procedures. Good record keeping and documentation, use of standard operating procedures and laboratory worksheets, and implementation of safety guidelines further improve the quality of performance.

The hospital blood bank is responsible for:

• Rapid response to urgent requests for blood components
• Checking pre-transfusion samples and requests
• Assessing of immunological compatibility between donor and patient
• Selecting of suitable blood component for each clinical condition
• Safe delivery and handling of blood components
• Inventory and stock management
• Interactions with the blood establishment.

Urgent Requests

All urgent requests for blood components and blood products should be notified to the laboratory by telephone. Blood bank staff should be given as much notice as possible to organise the work and assign appropriate priority to requests. The handling of any emergency situation benefits from clear and frequent communication with the hospital blood bank about the blood component requirements. A full crossmatch will take approximately 40-45 minutes from receiving the patient sample and request. In very urgent cases the time can be reduced to 20 minutes. This allows tests to exclude ABO incompatibility. In extremely urgent critical situations where blood is needed in less than 20 minutes, non-crossmatched group O blood should generally be made available for immediate use. Females of childbearing age should receive group O RhD negative red cells if the patient’s RhD type is not known.

Blood sampling and clerical checking

In pre-transfusion testing, careful checking is essential. Correctly identified and correctly labelled blood samples from the correct patient are fundamental to the provision of blood that is safe for transfusion. When a sample is received in the blood bank, a member of the staff must confirm that the information on the label and on the transfusion request are identical. The patient’s serological and transfusion history must also be checked and the results of current testing compared with those of previous tests. Any discrepancies must be resolved before any blood component can be released for transfusion.

Pre-transfusion testing

This involves testing the blood of the intended recipient to determine the ABO group and RhD type and to detect any clinically significant red cell antibodies (this procedure may be called “group and screen” or “type and screen”). If the screening test is positive further tests may be needed to identify the red cell antibodies so that compatible donor units can be selected. The patient’s serum is directly tested in the blood bank for compatibility with the donor red cells before transfusing RBC components (crossmatch). Some countries also require a further blood group check immediately before the blood is transfused.

Electronic issue (computer crossmatch)

Red cell units that are ABO and RhD compatible can be quickly issued for a patient on the basis of information in the blood bank information system, with no further testing, provided there are procedures in place to ensure that:

The patient’s ABO and RhD type have been tested and also confirmed on a second sample, retested on the first sample, or the patient has been found to be group O in the first instance

• The patient has no irregular red cell antibodies
• The grouping of the blood units is fully reliable
• The identification of the patient and his/her sample is fully reliable
• The patient’s previous results can be correctly identified and retrieved

Electronic issue can take as little as 10 minutes. Hospitals using electronic issue must comply with any applicable national guidelines.

Selection of blood component

The hospital blood bank will use the test results together with the information provided on the request form to select and label the correct blood component for the patient.

Safe delivery and handling of blood components

Errors at this stage of the clinical transfusion process are an important source of adverse reactions and events. Hospitals should have a policy that ensures that correct units are withdrawn from the storage location. Blood must only be stored in designated blood storage refrigerators with temperature monitoring charts and an alarm system.

Traceability

EU Commission Directives 2005/61/EC and 2002/98/EC (2005), require full traceability of blood and blood components, from donor to recipient and vice versa. Blood establishments and hospitals must have a system that permits identification of each unit of blood component and its final destination. A system that has proved effective in the UK is the so-called ‘bag & tag’ label system. (Fig 6.3) When a unit of blood component is prepared for a patient, a paper tag is printed from the laboratory computerised system. This includes patient identifying information and two traceability labels bearing the donation number.

The tag is attached to the unit of blood component until it is transfused (or returned to the laboratory if unused). If transfused, one label from the tag is placed in the patient’s notes and the other returned to the hospital transfusion laboratory. The data from the returned labels is entered into the computerised system that records the fate of each component. Instances of nonreturned labels are monitored and corrective action taken. Many hospitals report 95% or greater traceability using this system.

Inventory and stock management

The hospital blood bank is responsible for management of the hospital’s blood stock. This includes maintining an inventory for each blood group, ensuring an average age of blood at time of issue, and monitoring the amount of blood that becomes out dated or is not used for other reasons. Stock levels should be set in conjunction with weekly use and activity in order to avoid overstocking and wastage. Where possible an information technology (IT) system should be in place that supports blood stock management and provides a full audit trail of all blood stock electronically scanned onto the system.

The hospital blood bank should develop a partnership working agreement with their Blood Establishment provider on how to deal with shortages of blood.

Maximum Surgical Blood Order Schedule (MSBOS)

A Maximum Surgical Blood Order Schedule is a hospital policy agreed between the blood bank, clinicians and hospital transfusion committee. It specifies the number number of units of blood that should normally be crossmatched for planned surgical procedures. It takes account of the likely need for transfusion and the response time for receiving blood following a request. An MSBOS should reduce blood bank workload by avoiding unnecessary crossmatching and should contribute to stock management and reduced wastage. It is agreed through consultation between the blood bank, clinicians and hospital transfusion committee. For procedures where electronic issue is used, there is no need for the MSBOS.