[18] CHAPTER VIII LESSON 2 Flashcards by Arriane Cyrel (MTI)

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

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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

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CROSSMATCH TESTS

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consists of mixing recipient plasma with cells directly obtained from the donor unit to detect ABO or blood group antibody incompatibilities.

serologic crossmatch

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indicates the donor unit is compatible and safe for transfusion

nonreactive serologic crossmatch

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Objective: To select [?] that can provide maximal benefit to the patient.

donor unitS

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Serologic Crossmatch Test:

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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

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Accomplished by mixing the recipient’s serum with donor RBCs and centrifuging immediately.

Immediate Spin Crossmatch

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Absence of hemolysis or agglutination indicates ABO compatibility

Immediate Spin Crossmatch

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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

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Once a clinically significant antibody has been detected, an antiglobulin crossmatch is required.

Antiglobulin Crossmatch

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The antiglobulin crossmatch consists of an immediate spin crossmatch with the recipient’s plasma and cells from the donor unit.

Antiglobulin Crossmatch

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The test system is then incubated at 37°C and completed with the antiglobulin test.

Antiglobulin Crossmatch

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Antiglobulin Crossmatch Enhancement media may be applied:

o Albumin
o LISS
o Polyethylene glycol
o Polybrene

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Observable reactivity and/or hemolysis at any phase of testing indicate incompatibility.

Antiglobulin Crossmatch

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Subsequent testing should include an anti - globulin testing phase and the addition of an autocontrol.

Antiglobulin Crossmatch

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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

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Report by Judd indicated that an electronic crossmatch to detect ABO incompatibilities was as safe as the serologic immediate spin test.

Computer Crossmatch

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eliminates the need for a serologic crossmatch, which reduces sample volume requirements and testing time.

Electronic crossmatching

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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)

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Involves testing the patient’s blood sample for ABO, Rh, and clinically significant unexpected antibodies.

Type-and-screen procedure

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Patient sample is stored in the blood bank ref for future crossmatch if blood is needed for transfusion.

Type-and-screen procedure

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The type-and-screen, coupled with an immediate spin crossmatch, is referred to as an

“abbreviated crossmatch”

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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