INCOMPLETE CROSSMATCH

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INCOMPLETE CROSSMATCH
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Intended Learning Outcomes (ILOs)

• Compatibility Testing
• Approaches Requiring Less Than a Complete
  Crossmatch
• Is the Crossmatch Really Needed?
• What can be given in an emergency transfusion?

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Why do we care?
Compatibility testing is done to avoid a
hemolytic transfusion reaction If the Host or
Recipient recognizes the donor RBC surface
antigens as foreign, the host will mount an
immune response to the donor RBCs
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Major Blood Groups
ABO
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ABO blood group antigens present on red blood
cells and IgM antibodies present in the serum
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Major Blood Groups
Rhesus
47 Antigens make up the Rhesus Blood Group The
most significant is the D antigen
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What is compatibility testing?

• Also called pretransfusion testing
• Purpose
• To select blood components that will not cause
  harm to the recipient and will have acceptable
  survival when transfused
• If properly performed, compatibility tests will
  confirm ABO compatibility between the component
  and the recipient and will detect the most
  clinically significant unexpected antibodies

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Compatibility testing

• Can be divided into 3 categories
• Preanalytical procedures
• Serological testing
• Postanalytical procedures

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Patient Identification

• Must confirm recipients ID from bracelet ON the
  patient
• Full patient name and hospital number
• Name of physician

http//www.usatoday.com/tech/news/techinnovations/
2006-07-17-chips-everywhere_x.htm
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Sample Identification

• The sample should also have the full patient
  name, hospital number, and physician
• Date and time of collection, phlebotomists
  initials
• All of this should be on the request form and the
  sample

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Specimen Tubes
Pink Top - EDTA
Red Top no additives
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Serological Testing

• 3 tests
• ABO/Rh
• Antibody detection/identification
• Crossmatch

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ABO/Rh Typing

• In the ABO typing, the forward and reverse MUST
  match
• In the Rh typing, the control must be negative
• Both of these will indicate what type of blood
  should be given

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Anti A
Anti B
Anti A
Anti B
A
B
Anti A
Anti B
Anti A
Anti B
O
AB
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Antibody screen

• Also called the indirect Coombs test or the
  indirect antiglobulin test
• The antibody screen will detect the presence of
  any unexpected antibodies in patient serum
• If antibodies are detected, identification should
  be performed using panel cells (with an
  autocontrol)
• IS
• 37 (LISS)
• AHG

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Crossmatching

• Purpose
• Prevent transfusion reactions
• Increase in vivo survival of red cells
• Double checks for ABO errors
• Another method of detecting antibodies

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Crossmatches

• According to the AABB Standards
• The crossmatch shall use methods that
  demonstrate ABO incompatibility and clinically
  significant antibodies to red cell antigens and
  shall include an antiglobulin phase

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Crossmatch
No agglutination compatible
Agglutination incompatible
Donor RBCs (washed)
Patient serum
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The procedure

• Donor cells are taken from segments that are
  attached to the unit itself
• Segments are a sampling of the blood and
  eliminate having to open the actual unit

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Crossmatch Procedure

• if antibodies are NOT detected
• Only immediate spin (IS) is performed using
  patient serum and donor blood suspension
• This fulfills the AABB standard for ABO
  incompatibility
• This is an INCOMPLETE CROSSMATCH
• If antibodies ARE detected
• Antigen negative units found and X-matched
• All phases are tested IS, 37, AHG
• This is a COMPLETE CROSSMATCH

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Crossmatches
Will Verify donor cell ABO compatibility Detect
most antibodies against donor cells Will
Not Guarantee normal survival of RBCs Prevent
patient from developing an antibody Detect all
antibodies Prevent delayed transfusion reactions
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Approaches Requiring Less Than a
Complete Crossmatch
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Type and Screen

• Determines the ABO-Rh of the patient and the
  presence of the most commonly found unexpected
  antibodies(elimination of the crossmatch ).

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Type and Screen

• If an emergency transfusion is required after
  type and screen alone, an immediate-phase
  crossmatch is performed.
• Blood given in this manner is more than 99
  effective in preventing incompatible transfusion
  reactions due to unexpected antibodies.

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Is the Crossmatch Really Needed?

• If the correct ABO and Rh blood type is given,
  the possibility of transfusing incompatible blood
  is less than 1 chance in 1000.
• ABO-Rh typing alone results in a 99.8 chance of
  a compatible transfusion,
• The addition of an antibody screen increases the
  safety to 99.94, and
• A crossmatch increases this to 99.95.

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Physician responsibility in ordering
uncrossmatched blood

• In an emergency (ER or OR), there may not be
  enough time to test the recipients sample
• It is your judgment that the risk of the patient
  dying from from anemia is greater than the risk
  of transfusing the patient without
  pre-transfusion testing

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What can be given in an emergency?

• Type-Specific, Partially Crossmatched Blood
• An ABO-Rh typing and an immediate-phase
  crossmatch
• An abbreviated format
• Macroscopic agglutination.
• This takes 1 to 5 minutes

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What can be given in an emergency?

• Type-Specific, Uncrossmatched Blood
• The ABO-Rh type
• Most ABO type-specific transfusions are
  successful.
• Caution should be used for patients who have
  previously received transfusions or have had
  pregnancies.

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What can be given in an emergency?

• Type O Rh-Negative (Universal Donor),
  Uncrossmatched Blood
• Type O blood lacks the A and B antigens
• Type O Rh-negative, uncrossmatched packed RBCs
  should be used in preference to type O
  Rh-negative whole blood.
• More than two units of type O Rh-negative,
  uncrossmatched whole blood, the patient probably
  cannot be switched to his or her blood type .

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Specific Recommended Protocol

1. Infuse crystalloids or colloids.
2. Draw a blood sample for typing and crossmatching.
3. If crossmatched blood is not ready to give, use
   type-specific or type O Rh-negative cells or type
   O Rh-positive cells for males or postmenopausal
   females without a history of transfusions.

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Summary

• The crossmatch shall use methods that
  demonstrate ABO incompatibility and clinically
  significant antibodies to red cell antigens
• If an emergency transfusion is required after
  type and screen alone, an immediate-phase
  crossmatch is performed before transfusion (an
  abbreviated format )
• If crossmatched blood is not ready to give, use
  type-specific or type O Rh-negative cells

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