compatibility testing blakes flashcards
Blood transfusions needed to
Recipient Identification & Sample Collection and Processing
Blood Bank Testing
Blood Type and Antibody
Compatibility Blood Selection and compatibility
Recipient Identification & Transfusion
Compatibility testing involves all the steps in the
identification and testing of a donor unit and a
proposed recipient’s blood
Crossmatching is a part of
is part of compatibility testing
Compatibility Testing
Involves mixing _________
No what or what indicates compatibility
- Involves mixing donor RBCs and recipient serum or plasma
- No agglutination or hemolysis indicates compatibility
- Agglutination or hemolysis indicates incompatibility
Crossmatching serves and provides secondary means of
- Serves as a double check of ABO errors
- Provides a second means of detecting antibodies
According to the AABB Standards, crossmatching:
- “shall use methods that demonstrate ABO incompatibility
and clinically significant antibodies to red cell antigens and
shall include an antiglobulin phase.”
IS Crossmatch
- IS crossmatching is
performed when the recipient has
no evidence of an antibody - In the current sample OR
- In the historical record
- Recipient serum and donor RBC
suspension are mixed and
immediately centrifuged - Fulfills AABB standards
for detecting ABO incompatibility
Extended crossmatch
- All phases (IS, 37° C, antihuman
globulin [AHG]) are performed if the
patient demonstrates a
clinically significant antibody - In the current sample OR
- In the historical record
- If the patient has
autoantibody, autoadsorbed serum
may be used
Causes of Positive Results in the
Serologic Crossmatch
Incorrect ABO grouping of the patient or donor
An alloantibody in the patient’s serum reacting
with the corresponding antigen on donor RBCs
An autoantibody in the patient’s serum reacting
with the corresponding antigen on donor RBCs
New alloantibody
Alloantibody to low-incidence
Warm-reactive autoantibody
Donor positive DAT
Computer
Crossmatching
(EXM)
Makes a final check of
ABO
compatibility in the selection of
units instead of a serologic IS
procedure
Computer
Crossmatching
(EXM)
The recipient must not have what
The recipient must not have an
antibody (or antibodies) in the
current sample or have a
history of antibodies
Computer
Crossmatching
(EXM)
what are used to provide anther measure of safety
Bar codes
Limitations of crossmatching
An acceptable crossmatch
does not guarantee
a successful transfusion
– Adverse transfusion
reactions may still occur
– A negative antibody screen
does not guarantee that the
recipient does not
have significant antibodies
– A compatible crossmatch
does not
Guarantee survival of RBCs
Pretransfusion Will…
If performed correctly
Verify in most
cases components are ABO
Compatible.
Detect most
clinically significant unexpected
antibodies.
Transfusion Request Form
Transfusion Request Form
can be
Can be oral, electronic or written and must include information sufficient to positively
ID patient.
Transfusion Request Form
How many identifiers required and what types
2
- Patient full name
*Unique ID number
*Other identifier
*DOB
*Driver’s license number - Photographic ID
Transfusion Request Form
what is a drug and requires what
Blood is a drug and requires physician prescription.
Transfusion Request Form
Special Needs:
CMV negative, Irradiated, etc.
Transfusion Request Form
Reject Requisition if
Information incomplete or lacking
inaccurate
Illegible
Specimens
General Patients
Expires on 3rd day at midnight
Neonates specimens
Expires at 4 months of age
Give type O RBCs
Elective Surgery Patient’s specimens
Up to 30 days prior to surgery
Restrictions:
1. No history of alloantibodies
2. No history of pregnancy or transfusion within the last 3 months
3. Negative antibody screen
Recipient Blood Sample
Patient identification and sample labeling
- Full Name, Unique ID Number, Date and Time, Phlebotomist ID
- Labeled at patient bedside
Recipient Blood Sample
Sample collection tubes
- Samples may be plasma or serum
Recipient Blood Sample
Age of sample
- The limit is 3 days if the patient has been recently transfused or is pregnant
- Infants - specimen good till neonate turns 4 months
Recipient Blood Sample
Sample collection and appearance
*Hemolyzed samples or samples contaminated with intravenous fluids must be re-collected
Recipient Blood Sample
Specimen Storage
- Sample and sample from donor RBCs must be stored at 1-6oC for 7 days AFTER transfusion.
Previous Records
Current blood ABO and D typing must be compared with
results performed over
the past 12 months
Previous Records
- SECOND sample to confirm
ABO/Rh if no history (use of PPID eliminates
need for second sample)
Previous Records
The most significant information is
history of clinically
significant antibodies
Previous Records
- Specificity compared to ______
- Regardless of current results, _________________________
- Specificity compared to current antibodies detected.
- Regardless of current results, antigen negative blood MUST be provided.
Previous Records
Previous records must also be consulted for
any significant
event related to testing or transfusion
Pretransfusion
Testing
Type and Screen
- ABO and D typing
- Discrepancies should be resolved
before transfusion - Antibody detection
- Unpooled reagent RBCs should be
used - When done correctly, will detect
99.9% of unexpected antibodies
Pretransfusion
Testing
Crossmatching demonstrates what
- Demonstrates ABO incompatibility
and clinically significant antibodies
to RBC antigens
Repeat Testing of Donor Blood
Whole blood and RBCs
must be re-typed to
confirm the correct ABO
labeling
Repeat Testing of Donor Blood
ABO testing is performed
on
all units
Repeat Testing of Donor Blood
D testing is performed only
on D-negative units
Repeat Testing of Donor Blood
Weak D testing is not.
required
Repeat Testing of Donor Blood
Records are kept for
5 years
Selection of Donor Units\
D Antigen
- D-negative units
should be given to D-
negative recipients,
especially women of
child-bearing age - Antigen-negative
blood should be given if
anti-D antibody is
formed
Selection of Donor Units
Recipients
with Antibodies
- Antigen-negative
units are recommended
for the following
antibodies: - ABO
- Rh
- Kell
- Duffy
- Kidd
Probability in Blood Banking
of units needed/frequency of antigen negativity
Probability of finding antigen negative units
Frequency of antigen negative
* 100 – frequency of antigen
Probability in Blood Banking formula
of units needed/
Frequency of antigen-negative
The patient has anti-K. How many units will you
need to antigen type to find 4 compatible units?
4/.91= 4.39, approximately 5 units
The patient has anti-K and anti-C. How many units
will you need to antigen type to find 4 compatible
units?
4/ (.91)*(.32)= 13.7
Labeling (“Tagging”)
Blood Products
Requirements for the tag on a crossmatched donor unit:
- Recipient’s two independent identifiers
- Unique donor unit number or pool number
- Interpretation of crossmatching
Labeling (“Tagging”)
Blood Products
Required to verify and document at time of issue:
- Recipient’s two independent identifiers
- Recipient’s ABO group and Rh type
- Unique donor unit number or pool number
- Donor ABO group and, if required, Rh type
- Interpretation of crossmatch
- Special transfusion requirements
- Expiration date
- Date and Time of issue
Issuance of Blood Components
-The same approach used to properly identify the
patient before _____________
The same approach used to properly identify the
patient before sample collection must now be
applied to verify that the recipient is indeed the
same person who provided the initial blood
sample for testing.
Issuance of Blood Components
The actual product and accompanying record of
testing must be ___________
verified as relating to the same
donor unit number.
Issuance of Blood Components
The bedside check just prior to blood
administration is
is the most critical step for
prevention of mistransfusion.
Issuance of Blood Components
A statement of compatibility must be retained as
part of the patient’s permanent medical record if
the blood is transfused.
Issuance of Blood Components
A label or tie tag must be attached to the
unit
stating the identity of the intended recipient, the
results of pretransfusion testing, and the donor
unit number.
Issuance of Blood Components
Machine-readable, especially barcode patient-
blood unit identification, is ideally suited to
is ideally suited to
bedside check requirements and has been
recently reported to significantly improve
transfusion practice.
Issuance of Blood Components
Issuance of Blood Components
Use of radio frequency identification devices
(RFID) to improve
identification at every stage
of pretransfusion testing.
Issuance of Blood Components
Whatever system is used, the information
should be verified at least
twice before the
transfusion of the blood product.
Issuance of Blood Components
Before blood is taken from the blood bank
to the patient treatment area, check
ABO and Rh results
Clinically significant unexpected antibodies
Adverse reactions to transfusion
Issuance of Blood Components
Before transfusion is initiated, a reliable __________
Issuance of Blood Components
A system of positive patient identification by
comparison of
wristband identification and
compatibility forms must be followed strictly.
Unused Blood Products
Blood products may be
reissued if
the closure has not
been entered and
If the unit has been kept
between the upper and lower
temperature conditions (1° to
10° C for RBCs)
If the unit was stored at room
temperature, it should be
returned within about 30
minutes or within a time
determined by the facility
Emergency Release
Release must be signed by physician
Tag on donor unit indicating emergency release: compatibility
and/or infectious disease
Patient name and identifiers
Donor unit number(s), ABO and D typing, expiration date
Retain segments from units for crossmatching
A massive transfusion is
is a total volume
exchange of blood within 24 hours
Massive Transfusion
Group O, D-negative unit is given in
an emergency
Massive Transfusion
If a D-negative unit is unavailable, group
group O, D-positive
blood can be given to D-negative individuals who are
not of child-bearing age
Massive Transfusion
ABO-identical unit is given once
the blood group is
established in the recipient
Maximum Surgical
Blood Order Schedule
Average number of blood units
used for surgical procedures is
determined in a __________
facility
Maximum Surgical
Blood Order Schedule
This number is used as the
standard blood order for
surgical procedures
Maximum Surgical
Blood Order Schedule
It may also be used as a guide
for the number of
autologous
units that can be donated
Typing and Screening Procedure
A typing and screening (T/S) procedure includes
ABO, Rh, and antibody screening
Typing and Screening Procedure
A T/S is ordered when a
surgical procedure uses
less than 1 unit of RBCs
Typing and Screening Procedure
Crossmatching is performed on the sample if
Blood is needed
Typing and Screening Procedure
The goal of a T/S is to conserve
the blood inventory
Crossmatching
Autologous Blood
- Procedures must be in place to
ensure that units are located
and transfused to the recipient
The process is monitored
manually or through
computerized tracking
methods
Crossmatching
Infants Younger Than
4 Months of Age
ABO and D typing must be
performed
Serum testing is not necessary
Antibody screening is
performed on the infant’s or
mother’s sample
If antibody is present, antigen-
Intrauterine Transfusions
Blood for intrauterine transfusion must be
compatible with
Blood for intrauterine transfusion must be
compatible with maternal antibodies capable of
crossing the placenta.
Intrauterine Transfusions
no fetomaternal what or what
Check for
Crossmatching testing is performed using
Fetal ABO and Rh known/not known situations
for group-specific/group O Rh negative products
Check for maternal antibodies/donor antigens.
No fetomaternal ABO or Rh incompatibility
Crossmatch testing is performed using the
mother’s serum sample.
Non-RBC
Products
Frozen plasma, platelet
concentrates, and
Cryoprecipitate do not need to
be crossmatched
Non-RBC
Products
Plasma products should be
ABO serum
compatible
Non-RBC
Products
- Cryoprecipitate and platelet
Concentrates may not need
to be ABO compatible
Non-RBC
Products
Apheresis platelets and
granulocyte concentrates may
need to be crossmatched if they
contain more than 2 mL of RBCs
Future of Transfusion Medicine
Patient blood management (PBM) programs
Personalized medicine.
