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What are the normal readings for Mantoux test?

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Posted on Wed, 18 May 2016
Question: How many mm of induration is a negative reading for the mantoux ppd reading- what is the mm # for negative result for mantoux tuberculin test (PPD)
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Answered by Dr. Naveen Kumar (1 hour later)
Brief Answer:
Induration size of 5mm and above are usually considered positive

Detailed Answer:
Welcome to health care magic, I share your concern and I will try to help you out in best possible way.

The( Mantoux test ) tuberculin skin test is one of the few investigations that are still widely used as an important test for diagnosing tuberculosis. Though very commonly used by physicians worldwide its interpretation always remains difficult and controversial. Various factors like age, immunological status coexisting illness etc influence its outcome, so also its interpretation.
There is no correlation between the size of induration and likelihood of current active TB disease but the reaction size is correlated with the future risk of developing TB disease.
If the induration exceeds 5mm, it is cosidered positive and there are different set of conditions which bring out different induration sizes like 10mm and 15mm etc..
On the other hand, a negative test does not always mean that a person is free of tuberculosis. People who have been infected with TB may not have a positive skin test (known as a false negative result) if their immune function is compromised by chronic medical conditions, cancer chemotherapy, or AIDS. Additionally, 10%-25% of people with newly diagnosed tuberculosis of the lungs will also have a negative result, possibly due to poor immune function, poor nutrition, accompanying viral infection, or steroid therapy. Over 50% of patients with widespread, disseminated TB (spread throughout the body, known as miliary TB) will also have a negative TB test.

I hope this helps you.
If you have any further query, I would be glad to help you.
If not, you may close the discussion and if possible you may rate the answer for me, so that I get a good feedback.

Dr. Naveen XXXXXXX
Medical Consultant.
Ebix, Inc.
YYYY@YYYY
Above answer was peer-reviewed by : Dr. Naveen Kumar
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Answered by
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Dr. Naveen Kumar

General & Family Physician

Practicing since :2008

Answered : 154 Questions

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What are the normal readings for Mantoux test?

Brief Answer: Induration size of 5mm and above are usually considered positive Detailed Answer: Welcome to health care magic, I share your concern and I will try to help you out in best possible way. The( Mantoux test ) tuberculin skin test is one of the few investigations that are still widely used as an important test for diagnosing tuberculosis. Though very commonly used by physicians worldwide its interpretation always remains difficult and controversial. Various factors like age, immunological status coexisting illness etc influence its outcome, so also its interpretation. There is no correlation between the size of induration and likelihood of current active TB disease but the reaction size is correlated with the future risk of developing TB disease. If the induration exceeds 5mm, it is cosidered positive and there are different set of conditions which bring out different induration sizes like 10mm and 15mm etc.. On the other hand, a negative test does not always mean that a person is free of tuberculosis. People who have been infected with TB may not have a positive skin test (known as a false negative result) if their immune function is compromised by chronic medical conditions, cancer chemotherapy, or AIDS. Additionally, 10%-25% of people with newly diagnosed tuberculosis of the lungs will also have a negative result, possibly due to poor immune function, poor nutrition, accompanying viral infection, or steroid therapy. Over 50% of patients with widespread, disseminated TB (spread throughout the body, known as miliary TB) will also have a negative TB test. I hope this helps you. If you have any further query, I would be glad to help you. If not, you may close the discussion and if possible you may rate the answer for me, so that I get a good feedback. Dr. Naveen XXXXXXX Medical Consultant. Ebix, Inc. YYYY@YYYY