How Long After PPD To Read (And Why)?

Exact Answer: 72 hours

Some diseases are not only painful but dangerous as well. There is a majority of unique diseases worldwide, some of them are curable, then, on the other hand, some of them don’t have any cure, medications Some sort of this disease is now very much known to the world. One of them is tuberculosis, which is again a very dangerous disease sometimes it is deadly as well.

There are several tests for several diseases and just like that, tuberculosis as well as a particular test which is called the PPD test. PPD test, also known as Mantoux test or Mendel–Mantoux test, tuberculin sensitivity test, Pirquet test, or is a tool which is used for the screening for tuberculosis (TB) and to diagnose tuberculosis.

How Long After Ppd To Read

How Long After PPD To Read?

Objective Total Time
For urgent results48 hours
For accurate results72 hours

Tuberculosis (TB) is not any disease that can be taken lightly. It is one of the most dangerous diseases as far to be known. No human wants to be contracted with the disease for obvious reasons as along with being a very painful disease it becomes deadly as well sometimes. It is an infectious disease that is caused by bacteria are known as Mycobacterium tuberculosis (MTB) bacteria.

Tuberculosis affects the entire human body but generally, the most affected part of a human body by tuberculosis is the lungs. It is not only limited to affecting the lungs only, it affects various other parts of the body as well. One can experience a hell of a lot of symptoms when you are contracted with tuberculosis, but some people don’t experience any symptoms of tuberculosis at all.

About 10% of latent infection cases are such that if the disease is left untreated then the progress of the active disease kills about half of the patient. In general, there are a lot of symptoms that an individual might observe while suffering from tuberculosis but the most typical symptoms of active tuberculosis are a chronic cough with blood-containing mucus, moderate or high fever, night sweats, and the person might experience weight loss.

Why Does It Take That Long After PPD To Read?

What happens in PPD is that a tiny amount of tuberculin, which is a protein, is injected into the skin of the affected person, in the forearms. Tuberculin is a sterile extract purified protein derivative (PPD) that is made from the bacteria that cause TB. Once after receiving the injection, there is a formation of a small pale bump where the injection has been given.

There are various methods to diagnose tuberculosis but the most common one is PPD. It is one method of determining whether a person is infected with Mycobacterium tuberculosis or not. But this test needs a lot of things to be pre-prepared, such as standardization of procedures, training, supervision, and practice of PPD, so that it can be done on any patient safely.

When it comes to reading the PPD test then, reading the skin test is all meant to detecting a raised, thickened local area of skin reaction which is referred to as induration. Induration is the most pivotal thing to detect, the redness or bruising is not. Reading of skin test should not be done into any jiff.

It is always recommended to read skin tests within 2-3 days i.e, 48-72 hours after the injection because the size of the induration is maximal after 48-72 hours of injecting the protein into the skin. Although, when it is asked that what is standard timing of reading the test then the answer is after 48 hours of injection. As tests read after 72 hours are underestimate the size of the induration and are not that much accurate.


Tuberculosis is not any kind of disease that can be identified by the symptoms only. There are a bunch of symptoms one can feel while suffering from tuberculosis. It is one of the most dangerous and deadliest diseases.

In earlier times there were not any treatments that have been discovered to cure tuberculosis. But medical science is touching grim milestones every day and now is so advanced that the proper treatment, tests, and medications are available for everyone. PPD is one of the tests which is very reliable when it comes to identifying whether one is having tuberculosis or not.


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