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mentioned time period:

EDTA or Heparin : 2 days

Sodium citrate or sodium oxalate : 14 days

ACD or CPD : 28 days

Clotted whole blood should be tested within 14 days.

Additional Material Required for Slide and Tube Tests

Glass slides (50 × 75 mm), test tubes (12 × 75 mm), Pasteur

pipettes, isotonic saline, centrifuge, timer, and mixing

sticks.

322 Concise Book of Medical Laboratory Technology: Methods and Interpretations Test Procedure

Bring reagent and samples to room temperature before

testing.

Slide Test

1. Place one drop of Eryclone anti-A or anti-B or anti-AB

reagent on a clean glass slide.

2. To each reagent drop, add one small drop of whole

blood.

3. Mix well with a mixing stick uniformly over an area of

approximately 2.5 cm2

.

4. Rock the slide gently, back and forth.

5. Observe for agglutination macroscopically at 2

minutes.

Tube Test

1. Prepare a 2–3% suspension of the red cells to be tested

in isotonic saline.

2. Place one drop of Eryclone anti-A, anti-B, anti-A, B

into correspondingly labeled test tubes.

3. Pipette into each of the test tubes, one drop of the test

red cell suspension and mix well.

4. Centrifuge for 1 minute at 1000 rpm (125 g) or 20

seconds at 3400 rpm (1000 g) or incubate at room

temperature for 30 minutes.

5. Gently resuspend the cell button, observing for

agglutination macroscopically.

Interpretation of Results

Slide and Tube Tests

Agglutination is a positive test result and indicates the

presence of A and/or B antigen. Do not interpret peripheral

drying or fibrin strands as agglutination. No agglutination

is a negative test results and indicates the absence of A

and/or B antigen.

Remarks

1. (a) Eryclone® anti-A, anti-B and anti-AB reagent do not

show a reaction with crypt antigens (T, Tn, Tk activated

cells) (b) Eryclone® anti-B is truly negative reacting

with acquired B characteristics.

2. In the tube test procedure, it is recommended that

tubes with negative reactions should be recentrifuged

and results read again after 5 minutes so that weak

antigens are not overlooked.

3. As undercentrifugation or overcentrifugation could

lead to erroneous results, it is recommended that

each laboratory calibrates its own equipment and

determine the time required for achieving the desired

results.

4. Results of forward grouping obtained by using anti-A,

anti-B, anti-A, B reagent should always be reconfirmed

by performing reverse grouping with known red cells.

5. It is strongly recommended that red cells with known

ABO characteristics should be occasionally run,

preferably on a daily basis so as to control reagent

performance and validate test results.

6. After usage, the reagent should be immediately

recapped and replaced to 2–8°C storage.

ANTI-A1 LECTIN

Dolichos Biflorus Lectin for

Slide and Tube Tests

(Courtesy: Tulip’s Erybank Range)

Summary

Human red blood cells possessing the A antigen can be

broadly subdivided into two main subgroups namely A1

and A2 based on their reaction with A1 lectin. A2 subgroups

comprises of weaker subgroups of A such as A1, A2, A3, A4,

A5, A6, A0, etc.

Group A red blood cells which agglutinate with anti-A1

lectin are classified as subgroup A1, whereas red blood cells

which do not agglutinate with anti-A1 lectin are classified as

subgroup A2. It is estimated that about 80% of the group A

population are A1 and the remaining A2 or weaker. Anti-A1

lectin is especially useful in selecting blood for an A2 or A2B

recipient whose blood may contain anti-A1 antibodies.

Reagent

Erybank® anti-A1 lectin is a ready-to-use purified extract

of Dolichos biflorus seeds that is carefully calibrated to

differentiate most A1 cells from A2 cells. It contains a

phytohemagglutinin, which is virtually specific for A1

antigen on the human red blood cells.

Each batch of reagent undergoes rigorous quality

control at various stages of manufacture for its specificity,

avidity and titer.

Reagent Storage and Stability

a. Store the reagent at 2–8°C. Do not freeze.

b. The shelf life of the reagent is as per the expiry date

mentioned on the reagent vial label.

Principle

Human red blood cells possessing A1 antigen will

agglutinate in the presence of seed extract (lectins)

containing phytohemagglutinin specifically directed

toward it.

Blood Banking (Immunohematology) 323

Agglutination of red cells with Erybank anti-A1 lectin

is a positive test result and indicates the presence of A1

antigen. No agglutination with Erybank anti-A1 lectin

is a negative test result and indicates the absence of the

A1 antigen. Red blood cells that are positive with anti-A

reagent and negative with A1 lectin are classified as A2.

Note

1. In vitro diagnostic reagent for laboratory and

professional use only. Not for medicinal use.

2. The reagent contains sodium azide 0.1% as preservative. Avoid contact with skin and mucosa. On

disposal flush with large quantities of water.

3. Extreme turbidity may indicate microbial contamination/reagent deterioration. Such reagent should

be discarded.