The document summarizes the Schick test, which is used to determine susceptibility to diphtheria. The test involves injecting diluted diphtheria toxin intradermally and observing the reaction. If a red, swollen rash develops around the injection site within 2-4 days, the person is susceptible to diphtheria. Now outdated due to widespread vaccination, the Schick test worked by comparing the reaction at the toxin injection site versus the control site injected with inactivated toxin. A positive test indicated the need for diphtheria vaccination to develop protective immunity.

1. K V M COLLEGE OF PHARMACY
ACADEMIC YEAR 2020-2021
SCHICK TEST
PREPARED BY : VAISHNAV SR
VANDHANA G DEPT : MICROBIOLOGY
SECOND PHARM D

2. TABLE OF CONTENTS
• INTRODUCTION
• PRINCIPLE
• PROCEDURE
• RESULT INTERPRETATION

3. INTRODUCTION
• Schick test is invented between 1910-1911, a test used to determine whether or
not a person susceptible to diphtheria and causative agent
is Corynebacterium diphtheriae. It was named after its inventor Bela Shichk
(1877-1967), Hungarian born American paediatrician. It is an intradermal test. The
test is carried out by injecting intradermally into the skin of forearm 0.1 ml of
diluted (1/50 MLD) diphtheria toxin, while into the opposite arm is injected as a
control, the same amount of toxin which has been inactivated by heat.

4. DIPHTHERIA
• Diphtheria is a serious infection caused by strains of gram positive bacteria called Corynebacterium
diphtheria that make toxin (poison). It spreads easily from one person to another , diphtheria can be
prevented through the use of vaccines .
• Signs of diphtheria often appear within two to five days of the infection occurring . Some people don’t
experience any symptoms . The most visible and common symptom of diphtheria is a thick , gray
coating on the throat and tonsils .
• Other common symptoms are ;
• Fever
• Chills
• Sore throat
• Difficulty breathing and swallowing
• A loud , barking cough

5. PRINCIPLE
The Schick test works by injecting intradermally into the skin of forearm 0.1 ml of
diluted (1/50 MLD) diphtheria toxin. If the person is susceptible to the disease, a red
swollen rash appears around the injection area.

6. PROCEDURE
1.Inject toxin intradermally.
2.Wait for 2 to 4 days.

7. OBSERVATION OF RESULT
• Check redness/erythematic production and measure the zone of reaction in mm.

8. RESULT INTERPRETATION
• Negative reaction: If a person had immunity to diphtheria, no reaction will be
observed on either arm.
• Positive reaction: An area of in duration 10-15 mm in diameter generally
appears within 24-36 hours reaching its maximum development by 4-7 days, the
control arm shows no change. The person is susceptible to diphtheria.
• false positive reaction: A red flush develops in both arms, the reaction fades
very quickly, and disappears by 4th day. This is an allergic type of reaction found
in certain individuals
• Combined reaction: the control arm shows pseudo positive reaction and the test
arm is true +ve reaction, susceptible and need vaccination.

9. KEYNOTES
• Schick test is not indicated in very young children as they are susceptible and
require immunization
• No reaction – Protective immunity present.
• This test is now out dated due to vaccination and eradication.
• It also called toxigenic test.
• MLD stands for minimal lethal doses

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