Red cell compatibility testing

1. FARIDABANU ANSARI
LAB TECHNICIAN
UNMICRC

2.  Purpose:
◦ Selection of safest blood components for transfusion
◦ With acceptable donor’s red cell survival rates
◦ Without destruction of recipient’s red cells.
 Compatibility testing confirms ABO compatibility
and detects clinically significant unexpected
antibodies.

3. 1. Identification of Patient and their sample
• Patient’s full name and Hospital registration number
• Name of requesting physician
• Date and time of sample collection
• Initials of phlebotomist
• Information clearly written on requisition form and sample
2. ABO & Rh of recipient and donor blood
3. Test for clinically significant red cell antibodies on patient
serum

4. 4. Selection of appropriate unit of blood
◦ ABO & Rh compatible
◦ Expiration date
5. Performance of serological cross match
6. Labeling of component with patient identification
details
7. Issue after verification of patient identity along with
compatibility report and reaction form.

5.  Refrigerator 4°C for sample storage
 Tabletop Centrifuge
 Automated cell washer
 Centrifuge
 37°C Incubator
 Micropipette
 Donor blood sample
 Antisera
 Antihuman globulin reagent
 Pooled reagent red cell suspension 5%
(A, B, O)
 Bovine Albumin 6%
 Check Cells
 Normal saline
 Distilled water
 Test tubes
 Pasteur Pipettes
 Glass slides
 Plastic racks
 Marker pens

6.  Label 3 tubes (one for saline phase, one for albumin phase
and one for IAT phase) with patient and donor identification
for each unit to be crossmatched
 Add 2 drops/100μl of patients serum to each tube.
 Add 1 drop/50 μl of 5% donor red cell suspension to the
tubes containing patient’s serum
 Add 1 drop/50 μl of 22% albumin to the tubes labeled
albumin
 Mix the contents of tubes gently.

7.  Incubate the tube labeled as saline at room
temperature for 15min.
 Incubate the tube labeled albumin and IAT phase at
37°C for 30 min and 45-60 min respectively.
 Centrifuge the tubes with saline phase and albumin
phase at 1000 rpm for 1 min after incubation and
grade and record test results immediately

8.  To the test tube labeled IAT phase wash the cells 3
times using normal saline and completely decant
the supernatant after final wash to obtain a dry cell
button.
 To the dry button add 2 drops/100 μl of poly specific
AHG reagent and mix well.
 Centrifuge the test tube at 1000 rpm for 1 min
 Grade and record the result immediately.

9.  Perform ABO and Rh grouping on the patient sample and
selected blood units.
 Label one tube for each donor unit to be cross matched.
 Add 2 drops/100μl of patient serum to each tube.
 Add 1 drop/50μl of 5% donor red cell suspension to each
tube.
 Centrifuge immediately at 1000 rpm for 1min.
 Grade and record results immediately.

10.  Absence of agglutination and hemolysis is a
negative test result and indicates serologically
compatible cross match. This result is interpreted
as “Compatible”.
 Hemolysis or agglutination indicates the presence
of a serologically incompatible cross match. This
result is interpreted as “Incompatible”.

11.  Compatibility testing confirms ABO compatibility between
donor red cells and patient’s sample.
 Cross matching can be done routinely using test tube
method by Saline/Albumin/IAT phases or in emergency by
immediate spin technique.
 Even a fully compatible cross match cannot prevent
alloimmunisation of the recipient or detect some weakly
reactive antibodies.