This section will review compatibility requirements for plasma and the role played by patient blood group records in pretransfusion testing, including precautions related to their use. The discussion is not meant to be definitive or all inclusive.
- Compatibility requirements for plasma
- Importance of identification to transfusion
- Role of patient records
- This case
- Self study questions
- Further Reading
Plasma components must be ABO-compatible with the recipient's red blood cells, but not necessarily group-specific, as shown in Table 1. Note also that group AB plasma can be given to patients of all ABO groups and should be selected when the patient's blood group is unknown or cannot be determined.
Table 1. Plasma Component Compatibility.
O, A, B, AB
Once typed, do patients who require transfusion only with plasma components require ABO typing on each admission?
Because there are no standards that address this issue for plasma components, policies are set by individual transfusion services.Note that even a small volume of ABO-incompatible plasma can cause severe hemolysis if ABO antibodies with high titres are present in donor plasma:
Some hospitals have policies that require ABO/Rh typing on each new admission for patients requiring plasma components. An advantage of typing on each admission is that a crossmatch specimen would be readily available should RBC transfusion be required.
Before considering patient records, the importance of correct patient identification will be briefly reviewed. The most common cause of acute hemolytic transfusion reactions is patient misidentification. Such errors can lead to patients being transfused with donor blood of the wrong ABO group, resulting in severe hemolysis.
The stages where identification errors may occur include:
- Drawing the patient's pretransfusion specimen
- Labelling the patient's blood specimen, which must be done in the patient's presence
- Performing pretransfusion testing in the transfusion service
- Issuing donor blood from the transfusion service
- Identifying patient and donor unit immediately prior to transfusion
Most identification errors occur when collecting the patient's sample and when identifying the patient/donor unit prior to transfusion.
Whenever a pretransfusion specimen and requisition arrive in the transfusion service (TS), a history check is always done on the patient. Past records can be invaluable in several ways.
Preventing transfusion of incompatible blood due to patient misidentification
This is one of the major uses of past records. See Case B6 (ABO group inconsistent with records).
Preventing transfusion of incompatible blood due to weak antibodies
Records can protect the patient who has a weak, undetectable antibody. Even when an antibody is detectable, records can save the transfusion service time in obtaining antigen-negative donor red cells.
Identifying special transfusion requirements
Records increase transfusion safety by providing information about special transfusion requirements, e.g., the need for CMV-negative, irradiated, or washed blood components.
Identifying previous testing problems
Records provide access to information about previous testing problems such as ABO and Rh typing discrepancies and associated investigation and resolution, patients with positive direct antiglobulin tests (DATs) that remain positive over time.
Tracking transfusion-associated transmissible diseases
Patient records play a crucial role in tracking transfusion-associated transmissible diseases by facilitating tracebacks and lookbacks.
Although records play a critical role in the transfusion service, there are significant precautions associated with their use. Sometimes records may be relied upon without confirmation, e.g., if a patient has a record of having a clinically significant antibody but the antibody can no longer be detected, antigen-negative donor units would be crossmatched. In this case there is a logical explanation for the discrepancy and trusting the record protects the patient.
However, **most blood requests require current testing**. In particular:
RBC. Historical ABO blood groups are NEVER used to issue RBC.
Standards and regulations exist for using historical blood groups for RBC requests and specifically prohibit it. For example:
CSTM Standards (Canada). Regarding emergency transfusions: Clause G9.2.4 (verbatim). When time permits, the ABO and Rh group of the recipient shall be determined, and blood products of an appropriate group issued. Previous records shall not be used to obtain the recipient's ABO and Rh group for red cell requests.
CSA Standard Z902-04. Regarding emergency transfusion: Clause 10.9.3.3 (paraphrased) specifies that ABO group-compatible red blood cells may be transfused prior to completing compatibility tests if the recipients ABO group has been determined without relying on previous records.
Misidentification and clerical errors occur fairly commonly and can result in life-threatening hemolytic transfusion reactions.
ABO and Rh records on cards carried by patients are NEVER used for transfusion purposes since they are totally unreliable.Cases exist anecdotally and in the literature of records being wrong. Examples (based on the personal experience of author):
- A patient presented to her physician under a false identity (her girlfriend's) and was admitted to hospital for a therapeutic abortion under that identity; her ABO group disagreed with the record since her friend had been previously crossmatched.
- A patient was crossmatched due to a motorcycle accident and his ABO group did not agree with his record; patient was carrying an identity card of his older friend for the purpose of buying liquor in a bar, and the friend had been previously crossmatched.
- A patient's ABO group disagreed with her record based on testing two days ago; staff questioned why a new type and screen was ordered when a current valid sample existed but did the group anyway. Investigation revealed that an interning health professional was curious about his blood group and convinced a collector to take his sample under the identity of an existing patient.
Platelets and Plasma. As discussed, using historical blood groups for issuing platelets and plasma is not so clear. Because there are no standards that address this issue, policies are set by individual transfusion services.
In this case, patient HL had been tested 5 years ago and was on record as group A Rh positive with a negative antibody screen. Because the laboratory policy was to require an ABO/Rh typing on each new admission, the lab requested a blood specimen to confirm HL's ABO group before thawing and issuing the FFP.
- Plasma components must be ABO-compatible with recipient RBC, but not necessarily group-specific.
- Records of patient blood groups help to prevent misidentification and serve to increase transfusion safety in other ways, but there are significant precautions associated with their use.
- Historical blood groups must NEVER be used for RBC transfusion requests, because, if the records are wrong, ABO-incompatible RBC may be transfused that threaten the patient's life.
- Policies on using historical blood group records for plasma transfusion are set by individual facilities, some of which require ABO and Rh typing on each new admission.
- ABO-incompatible plasma can cause severe hemolysis, including even small plasma volumes if potent anti-A or anti-B are present in donor plasma.
- Advantages of typing patients who require plasma components on each admission include
- confirmation of patient's historical ABO blood group, making misidentification due to faulty records less likely
- crossmatch specimen would be readily available should RBC transfusion be required.
1. Where can patient misidentification occur?
2. What are some of the benefits of patient records when pretransfusion testing?
3.. What are some of the precautions related to using records in the TS?
4. Why cannot records be used to obtain the recipient's ABO and Rh group for RBC transfusion?
5. What are the compatibility requirements for FFP?
- Part 1: Clinical uses of FFP
- Part 2. Compatibility requirements for plasma <--You are here
- Part 3. Administering blood products
- Part 4: Investigating adverse events
- Part 5. Reporting adverse events