Topic 11: Compatibility Testing

Blood typing, Antibody screening, Antibody Identification, Crossmatching

Tests under pre-transfusion testing [4]

Request Testing > Verify Patient Identification > Collect and label patient sample > ABO and Rh typing > Antibody Screening > Compatibility Testing > SElect Compatible unites for transfusion

Pre-transfusion steps [7]

Requisition form / Blood request form

Physician's order should come in with...?

Patient's full name, unique identification number, and requested test

Requisition form should contain...?

in the presence of the patient : 2

Samples should be labelled [where] and should contain at least ___ unique identifiers [Separate answers with :]

Red Cells > Serum or Plasma

The recipient's Red Cells must be tested for clinically significant antibodies. T/F? If true write "TRUE", If false, write "Wrong word > Right word"

Minor crossmatching

Test replaced by Antibody screening

Major Crossmatching

Routinely performed Crossmatching in the lab

Clerical Errors

Most common errors that may occur in the laboratory

Patient Identification

In venipuncture, what is the most important step?

72 hours

Ideal age on the acceptable specimen for testing

A unique identifier must always be assigned which must remain with the patient even after they have been identified

If the patient's identity is unknown...?

May > May not

Nameplates on the wall or bed labels may be used to verify identity. T/F? If true write "TRUE", If false, write "Wrong word > Right word"

In Vitro hemolysis

refers to the hemolysis of the sample due to poor phlebotomy techniques

TRUE

In Vitro hemolysis of recipient samples for pre-transfusion testing Cannot be used. T/F? If true write "TRUE", If false, write "Wrong word > Right word"

Serum/Plasma

Sample of choice for blood samples for pre-transfusion testing

Formation of small fibrin clots

Disadvantage of Plasma as a sample

10mL

Amount of specimen enough for all testing procedures

Disconnect Line for 5 minutes, Extract the first 10mL to discard, proceed to collection of patient sample

How to collect blood from IV line [3 steps] [Separate with ","]

1-6ºC

If testing cannot be performed immediately, samples should be kept at...?

Pregnancy, Transfusion

Conditions tthat can indicate opportunity for a humeoral immune response [2]

Critical phase

Samples used for compatibility testing or specimens used in pre-transfusion testing should ideally be collected during...?

2-5%

What must be prepared in pre-transfusion testing to remove interference with testing procedures

Trapped Red Blood Cells, Trapped Serum, Enhance Rouleaux formation

Fibrin clots can cause....? [3]

Segment

The tubing directly attached to the blood bag unit

Segmented tubing

RBCs for donor pre-transfusion compatibility testing can be prepared from the....?

Donor number

used to identify all records of testing and eventual disposal of all component parts of the unit of blood

Segment number

A numeric or alphanumeric system used to link the donor to the donor record, pilot tubes, blood container, and all components made from the original collection

Using lancet to make tiny hole in the segment, Cutting end of the segment with scissors, Transferring contents of segment into tube

3 ways to obtain donor red cells form segments

Transferring contents of segment into tube

Method of obtaining Donor RBCs from Segments usually done in the lab

Compatibility testing

Serological aspect of pre-transfusion testing

ABO grouping, Ph typing, TTI screening, Antibody screening

AABB standards when testing for the donor sample for Blood Collecting Facilities [4]

Transfusion Transmitted Infections

TTI stands for...?

Confirming ABO cell grouping, Rh typing except Weak D

AABB standards when testing Donor sample in Transfusion Service Facilities [3]

Blood Collecting Facility

Unit or institution that provides blood products

Red Cross

Example of Blood collecting facility

Transfusion service Facility

The facility tasked with performing compatibility testing

ABO, Rh, unexpected antibodies

Information that should be included in record of Patient Sample Testing [3]

ABO grouping

Most critical pre-transfusion serologic test

Reconfirm the ABO group of all units and the Rh type

For donors, the transfusion service facility doing the crossmatch must always...?

They underwent transfusion, they have been pregnant within 3 months prior to scheduled transfusion

For recipients, the patient's blood specimen must not be older than 72 hours especially if....? [2]

FALSE

If a clinically significant antibody has been previously identified and the current sample has now tested negative, the patient can receive packed RBC which is positive for the corresponding Antigen. T/F? If true write "TRUE", If false, write "FALSE"

Group O-packed RBCs

packed RBCs that can be used if the patient's ABO grouping cannot be satisfactorily determined and they need to be transfused ASAP

Invalid

If the diluent control of Rh typing is positive, the result of the Rh typing is....?

Direct Antiglobulin Test

If the diluent control is positive, ___ should be performed on the patient's RBC to determine whether uptake of autoantibodies or alloantibodies is responsible for positive control

chemically modified Rh Blood typing serum, 8% albumin control

If DAT is (+), Rh typing can be performed using...? [2]

Rh negative blood

Blood that should be given if Rh type of the recipient cannot be determined and transfusion is essential

REcipient's serum or plasma

In antibody screening, we are testing....? for the presence of clinically significant antibodies

37ºC

Clinically significant antibodies typically react at...?

To detect as many clinically significant unexpected antibodies as possible

Principle of Antibody Screening

ABO Compatible group-specific blood unit

In selection of appropriate donor units for transfusion, the first choice should always be...?

TRUE

If you are giving blood of a different ABO group, only packed Red Blood cells can be given. T/F? If true write "TRUE", If false, write "Wrong word > Right word"

AB, A, B, O

Suggested ABO Group selection order for transfusion of RBCs for Group AB cells [1st choice > 2nd choice > etc...]

A, O

Suggested ABO Group selection order for transfusion of RBCs for Group A cells [1st choice > 2nd choice > etc...]

B, O

Suggested ABO Group selection order for transfusion of RBCs for Group B cells [1st choice > 2nd choice > etc...]

O

Suggested ABO Group selection order for transfusion of RBCs for Group O cells [1st choice > 2nd choice > etc...]

TRUE

Rh negative blood is acceptable for Rh positive patients. T/F? If true write "TRUE", If false, write "Wrong word > Right word"

Rh negative female patients of child bearing age

Rh positive blood should not be given to Rh negative...? [Demographic]

no pre-formed antibody is demonstrable in the sera

Transfusion of Rh Negative male patients and female patients beyond menopause with Rh positive blood is acceptable as long as...?

TRUE

There is no need to provide antigen-negative RBCs for patients whose sera contains antibodies that are reactive only below 37ºC. T/F? If true write "TRUE", If false, write "Wrong word > Right word"

have been freshly obtained > are close to their expiry date based on needs of patient

Units that will definitely be transfused should be selected from units that have been freshly obtained. T/F? If true write "TRUE", If false, write "Wrong word > Right word"

Unusual Appearance, Correct labelling, Hermetic seal integrity

Donor units should always be examined visually prior to compatibility for...? [3]

Abnormal color change, turbidity, clots

What qualifies for unusual appearance of donor units? [3]

Crossmatching

Traditionally meant as the testing of the patient serum with the donor RBC

Final Check of ABO Compatibility, Detect presence of antibody

Main functions of Crossmatch [2]

No clinically significant antibodies were detected in antibody screening, No historical record exists of the detection of clinically significant unexpected antibodies

AABB standards state that tests to detect ABO incompatibility are sufficient if...? [2]

Minor Crossmatch, Major Crossmatch

Types of Crossmatch [2]

Minor crossmatch

RBCs of the Patient are matched with the donors serum. What test is this?

Major Crossmatch

Uses patient's serum versus donor's Red Cells. What test is this?

Saline Technique, Albumin Technique, Abbreviated Crossmatch, Coomb's test, Enzyme-treated compatibility test, Broad Spectrum Compatibility Test

Techniques in crossmatching [6]

Saline Technique

Crossmatching technique sed to detect or identify IgM antibodies that react optimally at room temperature

anti-M, anti-N, anti-Lea, anti-Leb, anti-Lua, anti-P1

IgM alloantibodies detected in Saline Technique [6]

15-18ºC

Saline Technique is done at what temperature?

Enhancement Media

Albumin is an example of an...?

22 or 30% Bovine Albumin

Reagent for albumin technique

Albumin Technique

Crossmatch technique primarily used to detect or target IgG antibodies as well as warm-reacting Antibodies

Increases dielectric constant to reduce zeta potential

Action of Bovine Albumin

Should still be performed > can be eliminated

According to AABB standards, If the patient has no history of irregular antibodies and has a negative antibody screen, AHG phase of the crossmatch should still be performed. T/F? If true write "TRUE", If false, write "Wrong word > Right word"

Abbreviated crossmatch

Technique that detects only ABO Incompatibility

Patients with hyperimmune antibodies, when the procedure is not performed correctly, rouleaux, Infant specimen

False reactions may be seen both in Immediate Spin and Abbreviated crossmatch if...? [4]

Computer crossmatch

Major crossmatch done without the need for the test tubes or contact between the donor RBC and patient serum

Recipient has already been tested on more than 1 occasion

Computer crossmatch can only be used when...?

Recipient has clinically significant antibody, Recipient has ABO discrepancy

Computer crossmatch cannot be used under these 2 circumstances

Annual savings, Reduced sample requirements, Reduced handling of biological materials, Elimination of false reactions associated with the immediate spin crossmatch

Advantages of Computer crossmatch [4]

Coomb's Test

TEchnique used to detect incomplate or non-agglutinating antibodies as well as ones that bind to the complement

Enzyme-treated compatibility Test

Technique that Detects many clinically significant IgG and saline active IgM antibodies and can provide satisfactory backup test for IAT

One stage, Two stage

Methods of Enzyme-treated compatibility test [2]

One stage

Enzyme, Px serum, and dx Red CElls are incubated together. ETCT Method?

Two stage

Red Cells are pre-treated with an enzyme and then tested with px serum. ETCT method?

Bromelin, Trypsin, Papain, Ficin

Enzymes used in ETCT [4]

inability to detect certain antibodies in MNDS and Duffy blood group system

Drawback of ETCT

Protein Phase, Thermo Phase, Antiglobulin phase

Broad Spectrum compatibility Test phases [3]

Protein Phase

BSCT phase that detects prozone anti-Rh antibodies in serum albumin mixture on immediate centrifugation and ABO compatibility

Thermo Phase

BSCT phase that detects incompatibilities that may be undetected with incubation at 37ºC

anti-c, anti-E, anti-D

Antibodies detected in Thermo phase [3]

Antiglobulin phase

BSCT phase that can detect antibodies in acquired hemolytic anemia

Third order / Cryptagglutinoid antibodies

Antibodies that can be detected in Antiglobulin phase of BSCT [2 names]

Proper labeling, Proper release of blood, Re-identification of the patient prior to transfusion

Post Serologic Procedures [3]

Statement of compatibility, Label attached to unit stating identity of the intended patient

Special documents needed for proper release of Blood [2]

Incorrect ABO grouping of patient or donor, An Alloantibody or Autoantibody in the patient's serum reacting with the corresponding antigen on donor RBCs, Prior coating of donor RBCs with protein, Abnormalities in patient serum

Causes of Positive results in the serologic crossmatch [4]