Mantoux skin test or PPD skin test is used to diagnose tuberculosis (TB). It is used to check the hypersensitivity of an individual to tb.

Mantoux skin test procedure (ppd 2-step procedure)

There are various doses of tuberculin like 1 TU, 5 TU, 10 TU, and 250 TU. But mostly 5 TU is used.

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1. Intradermally injected 5TU ppd after cleaning the site with antiseptic.
2. Read the induration after two to three days.
   • If induration is more than 10 mm after three days then the PPD skin test considers positive.

Mantoux skin test results (Positive-Negative means)

PPD test results of more than 10 mm mean

If ppd test induration is more than 10 mm after ppd intradermally injection then the test result is positive. The patient has had or has live tuberculosis in his body.

Mantoux test negative

If there is no ppd induration after (72 HOURS) PPD intradermally injection then the test result is negative. It means the patient has not had primary tuberculosis.

False-positive TB test (PPD)

In the case of BCG vaccination, false-positive results can occur.

False-negative TB test (PPD)

There are the following cases that result in false PPD negative results.

1. Recent Tuberculosis Infection.
2. Energy
3. Very young age (less than six months)
4. Live virus vaccine
5. End renal Disease
6. Poor nutrition
7. Measles
8. Hodgkin’s disease
9. Sarcoidosis