DETECTION OF DRUG-INDUCED ANTIBODY And Procedure

DRUG-INDUCED ANTIBODY

Specimen

Reagents 

procedure 

Step 1:Adsorption of the drug on red cells

Step 2: Indirect antiglobulin test on drug-coated red cells

Results 

DETECTION OF DRUG-INDUCED ANTIBODY

Antibodies to certain drugs, such as penicillin, react with red cells on which the drug is adsorbed. These antibodies may cause hemolytic anemia. 

Specimen  Serum.

Reagents

1. One million units of penicillin or a daily dose of the drug under investigation.

2. Phosphate buffered saline, (PBS) PH 7.0 

3. Barbital buffer (0.1 M) pH 9.6 

4. Washed group 'O red cells

5. Anti-human globulin serum (AHGS).

Technique 

Step 1:Adsorption of the drug on red cells

1. Dissolve 1 million units of penicillin in 15 ml of barbital buffer.

2. Place 0.5 ml of washed group 'O' red cells in a test tube and add 7.5 ml of the penicillin solution.

3. Mix and incubate at room temperature for one hour. Gently mix the tube intermittently throughout incubation.

4. Wash the red cells three times in PBS.

5. Prepare a 5 % suspension of the cells. 

Step 2: Indirect anti-globulin test on drug-coated red cells

1. In a tube, mix 0.6 ml of patient’s serum and 0.2 ml of drug-coated red cell suspension.

2. Incubate at 37°C for 1 hour.

3. Examine for agglutination or haemolysis. If positive, report and do not proceed further.

4. If there is no agglutination, wash the cellsserum mixture three times in PBS, resuspending the cells after completely removing the supernatant each time.

5. After the third washing, add two drops of anti-human globulin serum (AHGS). Mix and stand for five minutes.

6. Centrifuge at 1000 g for 15 seconds.

7. Examine the tube for agglutination macroscopically by tapping the tube. Examine under the microscope by streaking a small drop on a slide with a Pasteur pipette

Results Agglutination of red cells indicates the presence of antibodies to the drug.