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4. Coomb’s control cells

5. Donor cells/reagent red blood cells.

Procedure

1. To properly labeled test tubes add two drops of serum.

2. Add an equivalent volume of 22 or 30% bovine albumin

(unless manufacturer’s directions state otherwise).

3. Add one drop of 2 to 5% saline suspended reagent or

donor red blood cells to each tube and mix.

4. Incubate at 37°C for 15 to 30 minutes.

5. Centrifuge for 15 to 20 seconds at 900 to 1000 g.

Observe for hemolysis and/or agglutination. Grade

and record the results.

Blood Banking (Immunohematology) 345

6. Wash the cells three or four times with saline and

completely decant after final wash.

7. Add AHG to cell button according to the manufacturer’s

instruction. Mix well.

8. Centrifuge and observe for reaction. Grade and record

the results.

9. Confirm the validity of negative tests by adding

Coomb’s control cells.

LISS (Low Ionic Strength Solution) Phase Indirect Antihuman Globulin Test

Specimen

Serum or plasma may be used. Preferably, freshly collected

serum should be used.

Reagents

1. Normal saline

2. LISS

3. Polyspecific AHG or monospecific anti-human IgG

reagent

4. Coomb’s control cells

5. Donor cells/reagent red blood cells.

Procedure

1. Wash reagent or donor red blood cells three times in

normal saline and completely decant saline after last

wash.

2. Resuspend the cells to a 2–5% suspension in LISS.

3. To properly labeled test tube, add two drops of serum.

4. Add two drops of LISS suspended red blood cell

suspension and incubate according to manufacturer’s

direction. Typically, this is 10 to 15 minutes at 37°C.

5. Centrifuge according to manufacturer’s direction.

Typically, this is 15 to 30 seconds at 900 to 1000 g and

observe for hemolysis and agglutination by gently

resuspending the cell button. Grade and record results.

6. Wash the cells three or four times with saline and

completely decant after final wash.

7. Add AHG to cell button according to the manufacturer’s

instruction. Mix well.

8. Centrifuge for 15 to 20 seconds at 900 to 1000 g and

observe for reaction. Grade and record the results.

9. Confirm the validity of negative tests by adding

Coomb’s control cells.

PEG-enhanced Indirect Anti-human Globulin Test

Specimen

Serum or plasma may be used. Preferably, freshly collected

serum should be used.

Reagents

1. Normal saline

2. PEG (20% in PBS)

3. Polyspecific AHG or monospecific anti-human IgG

reagent

4. Coomb’s control cells

5. Donor cells/reagent red blood cells.

Procedure

1. For each sample to be tested, mix 2 drops of test serum,

4 drops of 20% PEG in PBS, and 1 drop of 2–5% red

blood cell suspension.

2. Incubate according to manufacturer’s directions.

Typically, this is 15 minutes at 37°C.

3. Do not centrifuge.

4. Wash the cells four times with saline and completely

decant after the final wash.

5. Add AHG to cell button according to the manufacturer’s instruction. Mix well.

6. Centrifuge for 15 to 20 seconds at 900 to 1000 g and

observe for reaction. Grade and record the results.

7. Confirm the validity of negative tests by adding

Coomb’s control cells.

LIM (Low Ionic Medium Polybrene) Indirect Antihuman Globulin Test

Specimen

Serum or plasma may be used. Preferably, freshly collected

serum should be used.

Reagents

1. Normal saline.

2. Low ionic medium (LIM): To a 500 mL volumetric

flask, add 25 g of dextrose and 1 g of Na2 EDTA 2H2O.

Fill flask to 500 mL mark with distilled water.

3. Polybrene (Commercially available).

4. Resuspending medium: 0.2 M trisodium citrate, 5%

dextrose; working solution made by mixing 60 mL of

0.2 M trisodium citrate with 40 mL of 5% dextrose.

5. Washing solution (for anti-human globulin testing):

0.01 M trisodium citrate.

6. Polyspecific AHG or monospecific anti-human IgG

reagent.

7. Coomb’s control cells.

8. Donor cells/reagent red blood cells.

Procedure

1. Prepare 1% suspension of donor or reagent red blood

cells in the serum used for testing.

2. Add 1.0 mL of LIM solution. Mix and incubate for

1 minute at room temperature.

3. Add 0.1 mL of 0.05% Polybrene to each tube and mix.

4. Centrifuge according to manufacturer’s directions.

Typically, this is 10 seconds at 900 to 1000 g and

decants the supernatant fluid. Do not resuspend cell

button.

5. Add 0.1 mL of resuspending solution. Shake tube

gently and observe for persistent agglutination.

346 Concise Book of Medical Laboratory Technology: Methods and Interpretations If strength of agglutination is weak, examine the test

and a known negative control macroscopically. Do

not recentrifuge.

6. If desired, the anti-human globulin test may be

performed as follows:

a. Add 0.05 mL of resuspending solution to each

tube and mix well.

b. Wash the cells three times with 0.01 M trisodium

citrate solution.

c. Add two drops of AHG reagent to the cell button

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