SHOT estimates that the rate of “wrong blood in tube” errors is 1 in 2000.
To minimise the risk of ABO incompatible transfusion due to such errors, it is recommended that a second sample is requested for confirmation of the ABO group in new patients, provided this does not compromise the delivery of components required emergently.
Electronic issue is quickly replacing the IAT crossmatch due to the safety and security afforded by automated systems, as well as the sensitivity of antibody screens. Compatibility is determined by the LIMS system, without the need for serological testing of donor cells against recipient plasma.
Supplementary checks to be performed manually include:
Review of the request form and clinical details supplied.
Checking for potential duplicate patient registrations.
Special transfusion requirements.
Electronic issue can only be used for patients who have satisfied all of the following criteria:
Testing and entry of ABO/RhD group results is fully automated.
Only validated reagents and screening cells are used.
All samples and reagents are registered within the LIMS system with unique identifiers.
Results are transmitted electronically and automatically from the analyser to the LIMS.
The LIMS controls the suitability of patients for electronic issue.
Patients with clinically-significant antibodies are permanently excluded from LIMS.
There are at least two historical records of consistent ABO/Rh typing.
The current antibody screen is negative.
The patient is not excluded on clinical grounds (see IAT crossmatch below).
All labs using electronic issue must have documented contingency plans (including validated manual processes) for IT system failures. E.g.
Suspend routine testing.
All emergent crossmatch to be done by IAT.
Sending routine samples to other labs using the same LIMS for ABO/Rh typing and antigen screen.
Keeping a clear, documented audit trail for upload into the LIMS when it is available again.
For manual systems, one person should carry out the entire crossmatching procedure from beginning to end, one sample at a time. If this is not possible, then there should be an audit trail of individuals who took part in the process.
Indirect antiglobulin test (IAT) crossmatch is used to determine if recipient plasma is compatible with donor red cells. It should be used when electronic systems are unavailable or contraindicated.
IAT must be used for all patients:
Known to have clinically-significant red cell alloantibodies
When the antibody screen is positive
For neonates with maternal antibodies present.
With an ABO incompatible haematopoietic stem cell transplant.
Any patient who has had an ABO incompatible solid organ transplant in the last three months (to detect IgG anti-A or anti-B produced by passenger lymphocytes in the donor organ)
There must be an appropriate positive control with every crossmatch.
Immediate (saline) spin crossmatch is mainly used to detect ABO incompatibility, but it cannot be used to rule out weak anti-A or anti-B. It will not pick up IgG antibodies, and hence is not a suitable replacement for the IAT crossmatch. It is mainly used for emergency blood provision.
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