Blood Compatibility Testing Overview

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Questions and Answers

What is the maximum age of a patient sample that can be used for pre-transfusion testing?

2 days old

5 days old

3 days old (correct)

7 days old

Which of the following tests is NOT performed during donor testing at the collecting facility?

ABO testing

Blood type confirmation (correct)

Ab Screen

Rh testing

In patient sample testing, what must be checked aside from current results?

Previous records (correct)

Blood pressure records

Dietary restrictions

Weight history

Which type of sample is preferred for donor testing?

Plasma from integral tubing Signup and view all the answers

What is required during donor testing for Rh-negative units?

Confirm Rh only Signup and view all the answers

What is the primary purpose of conducting a type and screen before a surgical procedure?

To conserve blood inventory Signup and view all the answers

Which blood type must be given for intrauterine transfusions?

O, Rh negative Signup and view all the answers

What is the main requirement for autologous transfusions?

Collecting institution must have specific protocols Signup and view all the answers

Which of the following components does NOT require crossmatching due to prior screening for antibodies?

Fresh Frozen Plasma Signup and view all the answers

What must be done if antibodies are identified during blood typing?

Antigen negative blood is reserved or crossmatched Signup and view all the answers

What is the primary purpose of an antibody screen?

To detect unexpected antibodies in patient serum Signup and view all the answers

What action should be taken if unexpected antibodies are detected in a patient's serum?

Identify the antibodies using identification panel cells Signup and view all the answers

Which of the following statements regarding the minor crossmatch is true?

It is no longer necessary because donated units are screened for antibodies Signup and view all the answers

What does agglutination during a major crossmatch indicate?

Incompatibility between donor cells and recipient serum Signup and view all the answers

When calculating the number of units screened, which formula is used?

<h1>units screened = # units needed / frequency of antigen-negative units</h1> Signup and view all the answers

Which type of crossmatch is routinely performed in laboratories?

Major crossmatch Signup and view all the answers

What must be demonstrated in a major crossmatch?

ABO incompatibility and presence of unexpected antibodies Signup and view all the answers

What is the correct definition of a major crossmatch?

Donor red cells crossmatched with recipient serum Signup and view all the answers

What is the primary purpose of compatibility testing?

To ensure safe blood transfusions for the recipient Signup and view all the answers

Which of the following is NOT a component of compatibility testing?

Assessment of recipient's past medical procedures Signup and view all the answers

In compatibility testing, what must be confirmed regarding the recipient?

The recipient's correct identification Signup and view all the answers

What are the three categories into which compatibility testing can be divided?

Pre-analytical, Serological, and Post-analytical Signup and view all the answers

What is the significance of antibody screening in compatibility testing?

To identify potential unexpected antibodies Signup and view all the answers

If a patient does not have a wristband for identification, what is a necessary step?

Attach another form of positive identification Signup and view all the answers

What does the crossmatching procedure confirm?

ABO compatibility and presence of unexpected antibodies Signup and view all the answers

Which phase is NOT part of the pre-analytical procedures in compatibility testing?

ABO blood typing Signup and view all the answers

What is the definition of a massive transfusion?

A transfusion approaching or exceeding 5 liters within 24 hours Signup and view all the answers

When ABO-specific blood is unavailable, what should be given to patients with blood type A?

Blood type A or O only Signup and view all the answers

Which scenario is acceptable for Rh-positive blood transfusion?

To Rh-positive elderly females Signup and view all the answers

What is the priority in donor selection for ABO identical units?

ABO identical units should always be given first Signup and view all the answers

What must donor blood be phenotyped for?

To lack antigens corresponding to circulating antibodies Signup and view all the answers

When should Rh-negative blood be conserved?

When there are adequate supplies of Rh-positive units Signup and view all the answers

What is the first choice for blood type B patients when ABO-specific options are limited?

Type AB or O blood Signup and view all the answers

What is necessary for Rh-negative male patients receiving Rh-positive blood?

There must be no demonstration of anti-D in the sera Signup and view all the answers

What key information must be included on the labeling form of a blood unit?

Patient’s full name and ID number Signup and view all the answers

Which temperature range is required for the proper storage of RBCs?

1° to 10°C Signup and view all the answers

In an emergency release situation, which blood type is typically released when there is not enough time for testing?

O negative Signup and view all the answers

What action must be taken if a blood unit is not needed for transfusion?

It can be returned to the blood bank Signup and view all the answers

What must be done with the segments from released blood units during an emergency?

They should be retained for crossmatching Signup and view all the answers

Which document must be checked when issuing blood to ensure proper protocol?

Requisition form Signup and view all the answers

What should be documented in detail during an emergency release of blood?

Names, dates, and other details Signup and view all the answers

If a blood unit needs to be returned due to incorrect storage temperature, what is the maximum time frame for this to occur?

30 minutes Signup and view all the answers

Study Notes

Compatibility Testing Overview

Compatibility testing is crucial for blood transfusions to prevent harm.
It ensures the recipient and the blood component are compatible.
The process involves several stages, including identifying the patient's blood type, reviewing medical history, and cross-matching.

Pre-analytical Phases

Patient Identification: Verify the patient's identity using wristbands. This includes name, hospital number, and physician's details.
Unknown Patients: Positive identification is required for patients without wristbands (e.g., identification form attached to the patient).
Specimen Collection: Use appropriate tubes (e.g., lavender top - EDTA, red top - no additives). Issues like hemolysis (red blood cell breakdown), require rejection. If blood is drawn from an IV line, initial 10 mL must be discarded.
Review of Patient History: Review the patient's past transfusion history and other relevant medical details to help in the selection of the correct blood.
Sample Identification: The sample should include complete patient details (name, hospital number, location, physician name, date of collection and phlebotomist's initials.
Specimen Tubes: Lavender-top tubes contain EDTA (a blood anticoagulant). Red-top tubes collect serum (liquid portion of the blood without cells).

Serological Testing

ABO/Rh(D) Typing: Ensures compatibility of blood type and Rh factor, with forward and reverse reactions to confirm blood type.
Antibody Screening/Identification: Identifies unexpected antibodies in the patient's serum; If antibodies are found, specific blood needs to be identified, for example using a panel of blood cells (testing cells) to determine the type(s) of antibodies present. The results from these tests are then used to determine the correct type of blood for transfusion.
Crossmatching: Matches donor and recipient blood to identify possible incompatibility.
Cross Matching Types:
- Major crossmatch: This type matches the recipient's serum against donor red blood cells is performed to identify potential incompatibility and is necessary for all transfusions.
- Minor crossmatch: Matching the donor's serum against the recipient's red blood cells, was historically performed; however, since 1976 this is often not performed.
Crossmatch Methods:
- Immediate Spin Technique (IST): This method detects IgM antibodies.
- Conventional AHG (antihuman globulin) crossmatch: Detects IgG antibodies.

Post-analytical Phase

Labeling: Label the blood unit with recipient and donor information, including blood type, location, and physician details.
Inspection: Visually inspect the donor blood unit for abnormalities such as clots, discoloration, or contamination or other obvious issues, then prepare the unit for release to the recipient.

Issuing Blood

Verify the requisition form, donor tag and the unit label.
Check the date of expiration for the blood unit.
Ensure the correct blood unit is selected.
Release the blood to the recipient's care taker under the appropriate circumstances.

What if the Unit is Unused?

If blood is not needed for a transfusion, it can be returned to the blood bank.
The unit should remain unopened.
It should be stored at the correct temperature (e.g., 1-6°C for whole blood).
Return the unit within 30 minutes of issue if temperature is incorrect.

Special Circumstances

Emergencies: In emergencies, blood may be released without complete crossmatching and patient testing if signed for by a physician. A special tag must indicate it's not crossmatched.

Other Components

Some components, like fresh frozen plasma, platelet concentrates, and cryoprecipitate, don't require the same testing as whole blood before transfusion due to specific screening procedures.
ABO compatibility is still required for these components.

Neonatal Transfusions

Neonates (under 4 months) need specific considerations with regards to cross matching, for example exchange transfusion and top up transfusions. Tests such as antibodies with maternal serum might also need to be taken into account.

Massive Transfusion

Massive transfusion procedures should take into account the original sample may no longer reflect the patient's current condition.
ABO identical units are provided.
If antibodies were detected initially, then antigen negative blood is used for the massive transfusion.

Type & Screen

Type and screen testing is done to reduce blood inventory.
Usually, a crossmatch is not necessary to release the blood, if the blood is needed.

Autologous Crossmatching

Autologous blood refers to a patient donating blood for later use.
It often involves specific protocols, and may require different tests, in particular, the blood transfusion services.

Intrauterine Transfusions

For intrauterine transfusions, specific types of blood are used according to the mother and father's blood groups(Rh negative blood may be used).

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Description

Explore the critical components of blood compatibility testing, which is essential for safe blood transfusions. This quiz covers the procedures involved, including patient identification, specimen collection, and reviewing medical history. Understanding these processes will help ensure the safety and efficacy of blood transfusions.