Gel card technology

1. GEL CARD TECHNOLOGY
Guide – Dr Y. R. Gotekar
By – Dr Nainshi Bhatt

2. TESTS DONE IN BLOOD BANK
 ABO forward and reverse grouping
 Cross match
 Direct Coomb’s Test
 Indirect Coomb’s test
 DU Test

3. INTRODUCTION :-
 Dr. Yves Lapierre of Lyon, France, invented gel card
technology. He investigated gelatin, acrylamide gel, and glass
beads.
 As he searched for a way to trap red blood cell (RBC)
agglutinates during standardized sedimentation and
centrifugation.
 Gel particles provided the ideal material for trapping the
agglutinates.
 And this discovery led to a patented process i.e. the basis of
the gel-based tests.

4. HISTORY :-
 The gel test was developed in Europe by Dr Yves Lapierre at
DiaMed AG (Murten, Switzerland).
 Dr. Lapierre is the Director of the Multiple
Sclerosis Clinic at the Montreal Neurological
Hospital.
 He is an Associate Professor of Neurology and Neurosurgery
at McGill University

5. WHAT IS GEL TECHNOLOGY
-Gel Technology is an innovative approach to red cell
serology that is made to minimize problems associated
with conventional techniques of blood grouping.
- It also addresses issues of standardization and
documentation with unmatched sensitivity, specificity,
and efficiency.

6. INSTRUMENTS USED IN GEL TECHNOLOGY

7. INCUBATOR CENTRIFUGE

9. GEL CARD
- A plastic card with microtube is used instead of a TT.
- Gel card measures approx 5x7cm
- Consists of 6 or 8 columns.

10. MICROTUBE
Principle
Reaction
Chamber
Add Reactants
Serum/plasma/ red cells
Gel and Reagent

11. MICROTUBE
 The reaction chamber is where RBCs may be
sensitized (antigen-antibody binding) during
incubation.
 The column of each microtube contains dextran-
acrylamide gel particles suspended in a diluent with
reagents added, if applicable.

12. MICROTUBE
 The shape and length of the column provides a
large surface area for prolonged contact of the
RBCs with the gel particles during centrifugation.
 Microtubes filled with gel containing anti-IgG are
used for compatibility testing, antibody detection,
and antibody identification

13. VARIOUS TYPES OF CARDS
VARIOUS GEL
CVARDS
Rh-Subgroups
Single Antigen
Single Antigen Single Antigen

14. VARIOUS TYPES OF CARDS

15. GEL
 The gel particles make up 75% of the gel-liquid
mixture that is preloaded by the manufacturer into
each microtube.
 The gel particles :-
- Porous
- Serve as a reaction medium
and filter, sieving the RBC agglutinates according to
size during centrifugation

16. PRINCIPLE -:
 Haemagglutination test is based on -:
 Controlled centrifugation of RBCs through a dextran acrylamide
gel that contains predispensed reagents.
 Each microtube is composed of -:
- An upper (reaction) chamber that is wider than the tube
itself, designed to allow prior incubation of test serum and
RBCs.
- Narrow portion referred to as column.
 Serum and cell reaction takes place in a microtube

17. PRINCIPLE -:
 Sephadex gel matrix acts as a sieve.
• Large aggutinates remain on or near the top of gel interface.
• Smaller agglutinates pass partway through gel , dependingon
size.
• Unagglutinated cells pass to base of microtube to form a
button.
 Cells are always added prior to the serum so that serum
does not comes in contact with the gel-
This eliminates the wash phase as in conventional technique.

18. PROCEDURE
 Measured volume of Rbc’s and serum or plasma
 Dispensed into the reaction chamber
 If appropriate, the card is incubated and
centrifuged

19. AGGLUTINATION REACTIONS :- GRADING

20. INTERPRETATION OF THE TEST :-
1+
Aggl. red cell
in lower half
of gel col.
2+
RBC’s
agglutinates
throughout the
column
3+
Aggltuated
rbc’s in upper
half
4+
Solid band
of red cells
at top of gel
Negative

21. MIXED-FIELD REACTION :-
 - The reaction is
characterized by a layer of
agglutinated RBCs at the
top of the column
And a pellet of unagglutinated cells at the bottom of the
microtube.

22. MIXED-FIELD REACTION :-
False-positive mixed-field reactions :-
- When incompletely clotted serum is used in the
CAT test.
- Fibrin strands in such serum may trap
unagglutinated RBCs, forming a thin line at the top
of the column.
- Other unagglutinated cells pass through the column
during centrifugation and travel to the bottom of the
microtube.

23. APPLICATIONS :-
 ID-MTS and DG Gel8 are currently cleared by the FDA in the
United States for -:
- ABO forward and reverse grouping,
- Rh typing,
- DAT,
- Antibody screen,
- Antibody identification,
- Antibody titration,
- Antigen typing,
- Compatibility testing.

24. • The process of identifying an individual’s bld. grp. Involves
testing of red cells with known antisera (FORWARD TYPING)
and plasma with known group red cells (BACK/REVERSE
TYPING)
FORWARD AND REVERSE TYPING

25. FORWARD AND REVERSE
TYPING :
Reagents required
- ID DiaClon ABO/D + Reverse typing cards containing monoclonal anti- A,
anti- B & anti- D suspended in the gel. The tube labeled “Ctl” is the
negative control. Two tubes with “neutral” gel serve for reverse grouping
with A1 and B cells.
- ID – Diluent 2: modified LISS for
red cell suspension.
- Test cell reagents: ID DiaCell A1,
B, O (0.8 ± 0.1% suspension),
ready to use.

26. FORWARD AND REVERSE
TYPING
50 µl
Diacell
A1
50 µl
Diacell
B
50 ΜL
PATIEN
T
SERUM
50 µl
Patient
Serum
10 – 12.5µl Patients RBC
suspension 5%

27. FORWARD AND REVERSE TYPING
• Incubate the card at room temp. for 10 minutes
• Centrifuge the card for 10 minutes.

28. Gel Card Procedure
Crossmatch
ICT DU DCT
Major Minor
Cell Wash
3 Time
Donor
Cell
Patient
Cell
O Cells
EDTA
Sample Cell
EDTA
Sample Cell
Use Sediment
Packed Cell 10 µl 10 µl 10 µl 10 µl 10 µl
Diluent - 2.0 1 ml 1 ml 1 ml 1 ml 1 ml
0.8 % Red Cell Preparation
In 45° Angle 50 µl 50 µl 50 µl 50 µl 50 µl
In 90° Angle
Patient
Serum
25µl
Donor
Serum
25 µl
Patient
serum
25 µl
Anti-D
25 µl
Incubate at 37° C 15 min. 15 min. 15 min. 15 min.
Centrifuge
1 cycle
10 min. 10 min. 10 min. 10 min. 10 min.

29. MAJOR CROSS MATCH

32. Patient’s RBC
suspension Add 50 µl of
above soln.
Results
DIRECT COOMB’S TEST

33. O cell
suspension Add 50 µl of
above soln.
Results
Add 25µl of
patient serum
Centrifuge Incubate
INDIRECT COOMB’S TEST

34. PARTICLE GEL IMMUNOASSAY (PAGIA)
• Gel Technology now adopted with use of inert
polymer particles for detection of:
• Syphilis
• Paroxysmal Nocturnal Haemoglobinuria
• Leishmaniasis
• Sickle Hb Screening

35. ADVANTAGES :-
 Improved sensitivity and specificity, Easy to use,
simple to read
 No wash phase in IAT Minimal training
required . Reliable, reproducible results
 Easy storage and long shelf life of reagents. Easy disposal
of biodegradable cards
 Widest range of reagents and instrumentation

36. ADVANTAGES
 Compared with traditional tube technology the gel-
based tests provide :-
- A more stable endpoint
- More reproducible results
-Eliminating the variability associated
with
the physical resuspension of RBC buttons after
centrifugation and the subjectivity in interpretating
hemagglutination reactions.

37. DISADVANTAGS :-
 Special centrifuge to accommodate the microtubes
cards.
 Special incubators to incubate the microtube cards.
Pipette to dispose 25ul of serum.
 Expensive.

38. Thank you