[18] CHAPTER VIII LESSON 2 Flashcards
Traditionally meant the testing of the patient’s serum with the donor’s RBCs, including an [?] or simply an immediate spin phase to confirm [?].
antiglobulin phase
ABO compatibility
Two main functions of the serologic crossmatch test can be cited:
1. It is a final check of [?] between donor and patient.
2. It may detect the presence of an [?] in the patient’s serum that will react with antigens on the donor RBCs
ABO compatibility
antibody
CROSSMATCH TESTS
consists of mixing recipient plasma with cells directly obtained from the donor unit to detect ABO or blood group antibody incompatibilities.
serologic crossmatch
indicates the donor unit is compatible and safe for transfusion
nonreactive serologic crossmatch
Objective: To select [?] that can provide maximal benefit to the patient.
donor unitS
- Serologic Crossmatch Test:
If no clinically significant antibodies are detected and there is no history of antibody, a serologic test to detect ABO incompatibility is sufficient.
Immediate Spin Crossmatch
Accomplished by mixing the recipient’s serum with donor RBCs and centrifuging immediately.
Immediate Spin Crossmatch
Absence of hemolysis or agglutination indicates ABO compatibility
Immediate Spin Crossmatch
Incompatible immediate spin crossmatches may occur for many reasons and must be resolved prior to issuing units for transfusion. Possible reasons for incompatibilities and subsequent resolutions include the following:
1. [?] of recipient or of donor unit selected
2. [?] in the plasma not detected in antibody detection tests
3. Abnormalities in the [?]
Incorrect ABO grouping
Cold-reactive allo- or autoantibody
recipient’s plasma
Once a clinically significant antibody has been detected, an antiglobulin crossmatch is required.
Antiglobulin Crossmatch
The antiglobulin crossmatch consists of an immediate spin crossmatch with the recipient’s plasma and cells from the donor unit.
Antiglobulin Crossmatch
The test system is then incubated at 37°C and completed with the antiglobulin test.
Antiglobulin Crossmatch
Antiglobulin Crossmatch Enhancement media may be applied:
o Albumin
o LISS
o Polyethylene glycol
o Polybrene
Observable reactivity and/or hemolysis at any phase of testing indicate incompatibility.
Antiglobulin Crossmatch
Subsequent testing should include an anti - globulin testing phase and the addition of an autocontrol.
Antiglobulin Crossmatch
Possible reasons for incompatibilities include the following:
1. [?]is present in recipient’s plasma.
2. Alloantibody to a low-incidence present is on the [?].
3. [?] is present in the recipient’s plasma.
New alloantibody
donor unit red blood cells
Warm-reactive autoantibody
Report by Judd indicated that an electronic crossmatch to detect ABO incompatibilities was as safe as the serologic immediate spin test.
Computer Crossmatch
eliminates the need for a serologic crossmatch, which reduces sample volume requirements and testing time.
Electronic crossmatching
must contain donor unit information to include the donation identification number, component name, ABO group, Rh type, donor confirmation typing, and the interpretation of compatibility with the recipient.
laboratory information system (LIS)
Involves testing the patient’s blood sample for ABO, Rh, and clinically significant unexpected antibodies.
Type-and-screen procedure
Patient sample is stored in the blood bank ref for future crossmatch if blood is needed for transfusion.
Type-and-screen procedure
The type-and-screen, coupled with an immediate spin crossmatch, is referred to as an
“abbreviated crossmatch”
Causes of Positive Results in the Serologic Crossmatch
1. Incorrect [?] of the patient and donor
2. An [?] in the patient’s serum reacting with the corresponding antigen on donor RBCs
3. An [?] in the patient’s serum reacting with the corresponding antigen on donor RBCs
4. Prior coating of the donor RBCs with protein, resulting in a [?]
5. Abnormalities in the [?]
6. Contaminants in the[?]
ABO grouping
alloantibody
autoantibody
positive antihuman globulin test
patient serum
test system
Donor cells that demonstrate a [?] will be incompatible with all recipients tested in the AHG phase, because the cells are already coated with immunoglobulin or complement.
positive DAT
Imbalance of the normal ratio of [?)
- Multiple myeloma and macroglobulinemia
albumin and gamma globulin (A/G ratio)
Contaminants in the test system:
a. Dirty glassware
b. Bacterial contamination of samples
c. Chemical or other contaminants in saline
d. Fibrin clots may produce false-positive compatibility test results
SPECIAL CORCUMSTANCES
If the blood type of the recipient is unknown, group O red blood cells are required.
Emergency Transfusions
ABO group-specific red blood cells may be issued once a blood type is obtained.
Emergency Transfusions
Rh-negative red blood cell units are preferred but may be limited to women of childbearing age in order to conserve inventory
Emergency Transfusions
Select uncrossmatched, group O, Rh-negative or Rh-positive red blood cell units based upon patient’s sex and age.
Emergency Transfusions
is defined as the administration of 8 to 10 red blood cell units to an adult patient in less than 24 hours or acute administration of 4 to 5 units within 1 hour.
Massive Transfusions
The American College of Surgeons recommends transfusion of red blood cells, thawed plasma, and platelets in a ratio of 1:1:1 for effective blood component resuscitation.
Massive Transfusions
The goal of treatment is to restore blood volume rapidly to a level adequate to maintain hemostasis, oxygen-carrying capacity, oncotic pressure, and biochemical parameters.
Massive Transfusions
Pretransfusion testing may be abbreviated in infants less than 4 months of age.
Neonatal Transfusions
For ABO grouping, only anti-A and anti-B reagents are required.
Neonatal Transfusions
Select a group O, Rh-compatible red blood cell unit
Neonatal Transfusions
Either the infant’s or mother’s plasma may be used for antibody screening and any necessary compatibility testing.
Neonatal Transfusions
are indicated in severe cases of fetal anemia
Intrauterine transfusions (IUT)
are performed by inserting a needle into the umbilical vein using highresolution sonography to guide the procedure.
Intrauterine transfusions (IUT)
Fetal samples may be obtained for testing to include blood typing, direct anti -globulin test, antigen typing, and bilirubin levels.
Intrauterine transfusions (IUT)
Select a group O, Rh-negative red blood cell unit that is fresh, leukocyte-reduced, irradiated, negative for sickling hemoglobin, and antigen-negative, if applicable.
Intrauterine transfusions (IUT)
It is a procedure performed prior to a blood transfusion to determine whether donor blood is compatible with recipient blood.
CROSSMATCHING
is determined through matching of different blood group systems: ABO and Rh
Compatibility
Determined by directly testing for the presence of antibodies against a sample of donor tissues or blood.
Compatibility
Routinely used as the final step of pretransfusion testing
CROSSMATCHING
Purpose of Crossmatching
To detect:
Irregular antibodies
Errors in ABO grouping
Clerical errors in patient identification
Result recording
The crossmatch will detect the following:
1. Most [?] directed against antigens on the donor red blood cells
2. Major [?] in ABO grouping, labeling, and identification of donors and recipients.
recipient antibodies
errors
will detect incompatibilities between the donor and recipient that will not be evident on blood typing.
Crossmatching
Crossmatching 2 types:
Patient’s serum with donor’s cells
Major Crossmatch
Determine whether the patient has an antibody
Major Crossmatch
Major Crossmatch
Determine whether the patient has an antibody which may cause:
Hemolytic transfusion reaction
Decreased cell survival of donor cells
Most important crossmatch
Patient’s cells with donor serum
Major Crossmatch
Determine whether there is an antibody in the donor’s serum directed against an antigen on the patient’s cells.
Minor Crossmatch
The presence of a low-incidence antibody in the donor’s serum would not cause a transfusion reaction because it would be diluted in the recipient’s serum
Minor Crossmatch
The mixture of erythrocytes and serum are observed for
hemolysis or microscopically for agglutination.
Presence of Agglutination/Hemolysis:
INCOMPATIBLE
Absence of Agglutination/Hemolysis:
COMPATIBLE
The crossmatch procedure combines [?] with red cells from the donor.
serum or plasma from the recipient
• Compatible crossmatch:
No agglutination and no hemolysis at any phase of testing. Donor unit can be transfused.
• Incompatible crossmatch:
Hemolysis or agglutination at any phase of testing. Donor unit is not acceptable for transfusion.
Crossmatch Types
Uses procedures to demonstrate ABO incompatibility and clinically significant antibodies to red cell antigens.
Serologic crossmatch
There are two types of serologic crossmatches:
immediate-spin for ABO compatibility and antiglobulin for clinically significant antibodies.
Uses computer to make the final check of ABO compatibility in the selection of appropriate donor units.
Computer crossmatch
Recipient cannot possess clinically significant antibodies in the current or any previous sample.
Computer crossmatch
In emergency situations, [?] are issued uncrossmatched if the patient’s ABO group is unknown.
group O RBCs
is also provided if the D type is unknown, especially if the patient is a woman of childbearing age.
D-negative blood
refers to total volume exchange of blood through transfusion within a 24-hour period, whether in an infant or in an adult patient
Massive transfusion
The blood products transfused in 24 hours approximate or exceed the recipient’s original blood volume (approximately [?] of whole blood in an average man).
10 to 12 units
The recipient’s circulation contains almost entirely transfused blood and essentially no autologous blood.
Massive Transfusion
If the average use for a particular surgical procedure is less than 1 unit of RBCs, the pretransfusion order is a T/S unless clinically significant antibodies are found.
Type and Screen Protocols
If blood is subsequently needed, the T/S specimen is used to crossmatch units by the immediate spin or computer crossmatch technique.
Type and Screen Protocols
Autologous blood is blood donated by the prospective recipient for later use, usually in the context of elective surgery.
Crossmatching Autologous Blood
The extent of pretransfusion testing for autologous units varies in individual facilities.
Crossmatching Autologous Blood
Initial compatibility testing in an infant must include
pretransfusion ABO and D typing with no serum testing
ABO and D type does not need to be repeated for the duration of the current admission or until the neonate reaches the age of [?], whichever is sooner.
4 months
An [?] needs to be performed on either the infant’s or the mother’s sample.
initial antibody screen
If clinically significant antibodies are found, the blood for transfusion needs to be [?] or compatible in an [?]
antigen-negative
antiglobulin crossmatch.
Crossmatching continues until [?] is no longer detectable in the infant’s serum.
maternal antibody
If the antibody screen is negative, no crossmatches or repeat screens are needed during the current admission as long as RBCs are used that are ABO compatible with the infant and specific for the infant’s
Dantigen typing (or D-negative).
contain almost no red cells and do not need to be crossmatched.
Frozen plasma, platelet concentrates, and cryoprecipitate
[?] and especially [?] may contain red cells, but they need to be crossmatched only if the unit contains more than [?] of red cells.
Apheresis platelets; granulocyte concentrates
2 mL
