The Schick test, invented between 1910 and 1911, is a test used to determine whether or not a person is susceptible to Diphtheria.

1. SCHICK TEST
MD ALTAMASH AHMAD
Pharm D 2nd year

2. Definition
◦ The Schick test, invented between 1910 and 1911, is a test used to determine
whether or not a person is susceptible to Diphtheria.
◦ It was named after its inventor, Béla Schick (1877–1967), a Hungarian-born
American paediatrician.
◦ The test was created when immunizing agents were scarce and not very safe,
however as newer and safer toxoids were made available there was no more
requirement for susceptibility tests.

3. Diphtheria
◦ Fatal acute infectious disease caused by toxigenic strains of Corynebacterium
diphtheria (Gram positive, rod shaped, non-motile, non-spore forming bacteria)
◦ It may cause tough, grey obstructive pseudo membranes in the upper respiratory
tract leading to difficulty in breathing which might extend into the larynx and
bronchial airways or damage to myocardium and other tissues.
◦ It spreads through close contact or droplet infection from a infected person’s
sneezing, coughing or infected clothes or carrier.
◦ Took its name from Greek word “diphthera” meaning leather. Named in 1826 by
French physician Pierre Bretonneau.
◦ In the past, disease was called as general disease or killer disease because there was
no treatment and was the cause of high mortality in children.
◦ It was said that the disease killed as many as 80% of the children below 10 yrs.

5. Problem Statement :
Endemic disease
Declining trend of diphtheria due to increasing coverage of child population by
immunization .
Reported cases - 1987- 12952, 2011- 4286
In 2012, with a little over 2,500 cases - the lowest since 1999, India seemed to be
winning the battle against the disease. But by 2016, this increased to 3,380 cases
- 47.63% of the world's total. By 2017, this increased to 5,293 cases - 60% of the
total cases in the world.
Inadequate immunisation, patchy coverage of booster doses and the
unavailability of accessible drugs have combined to give India the dubious title of
being the world leader in diphtheria cases.
Vaccines – DPT (Diphtheria, Pertussis & Tetanus), DTP(w), DTP(a), DT (diphtheria
tetanus toxoid)

6. Procedure of the Schick test
◦ A small amount (0.1 ml) of diluted (1/50 MLD*) diphtheria toxin is injected
intradermally into one arm of the person and a heat inactivated toxin on the
other as a control.
◦ Result :
◦ If a person does not have enough antibodies to fight it off, the skin around the
injection will become red and swollen, indicating a positive result. This
swelling disappears after a few days.
◦ If the person has an immunity, then little or no swelling and redness will occur,
indicating a negative result.
◦ *1/50 MLD = 1 part of 50 % Minimal Lethal Dose (MLD)

7. Interpretation of test
◦ Results can be interpreted as:
1. Positive: when the test results in a wheal (raised mark on skin) of 5–10 mm
diameter, reaching its peak in 4–7 days. The control arm shows no reaction.
This indicates that the subject lacks antibodies against the toxin and hence is
susceptible to the disease.
2. Pseudo-positive: when there is only a red colored inflammation
(erythema)and it disappears within 4 days. This happens on both the arms
since the subject is immune but hypersensitive to the toxin.
3. Negative reaction: Indicates that the person is immune.
4. Combined reaction: Initial picture is like that of the pseudo-reaction but the
erythema fades off after 4 days only in the control arm. It progresses on the
test arm to a typical positive. The subject is interpreted to be both
susceptible and hypersensitive.