Introduction
Tuberculosis is a serious lung infection. It occurs due to the bacteria called Mycobacterium tuberculosis. It is an airborne disease and spreads from the person affected by tuberculosis. It is also known as the Mantoux test or tuberculin skin test. The purified protein derivative (PPD) test is harmless and the complications are very rare. This test uses dead bacteria, so there is no chance of infection spreading. The Mycobacterium tuberculosis bacteria stay inactive inside the lungs for many years.
How Is the Purified Protein Derivative Test Performed?
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The sample is collected from the inner part of the forearm.
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Alcohol is used as a disinfectant to wipe the skin.
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Then a purified protein test shot is given in the topmost layer of skin.
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The individual might feel a sting during the insertion.
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A small bump or wilt in the skin is formed on the injected site. It usually settles down after a few hours.
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The individual must consult the medical professional after two to three days.
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The nurse will observe the changes in the injected site.
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Necessary preventive measures are taken according to the skin reactions.
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The risk of redness and swelling in the arms is very low.
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The individual with a previous history of positive purified protein derivative test (PPD) will have moderate to severe reactions.
How Should One Prepare Before Taking a Purified Protein Derivative Test?
The individual should follow the instructions given below before taking a purified protein derivative test.
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Fasting is not necessary for the purified protein derivatives (PPD) test. Consume a healthy breakfast and drink more fluids the day before the screening. It gives energy before and after the test.
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The individual must intake plenty of water a few days before the test. This keeps the body hydrated and it is easier to take blood tests.
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The individual should inform the doctor about their medical history, medications and drug allergy. Because it may lead to inaccurate results.
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Inform the doctor if there was an allergy during the first shot of the purified protein derivative test.
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It is cost-effective and the duration of the purified protein derivative test is three days.
What Are the Purposes of the Purified Protein Derivative Test?
The following are the purposes of the purified protein derivative (PPD) test three days.
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The healthcare worker must take a routine purified protein derivative (PPD) test to prevent tuberculosis infection at an earlier stage.
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The patients affected by the acquired immunodeficiency virus (AIDS) must take a screening with a purified protein derivative test.
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It is better to take a purified protein derivative test earlier if the individual feels like he is exposed to an infected person.
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The patient affected by persistent productive cough and fever for more than four weeks must take a purified protein derivative (PPD) test.
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Tuberculosis is a contagious disease and affects both the lungs. So if the individual has unexplained weight loss with physical exertion, he should take a purified protein derivative (PPD).
What Does the Result Indicate in a Purified Protein Derivative Test?
The results vary depending on the underlying medical conditions. They are as follows;
Negative Result:
- A negative result indicates that the individual is not infected by the Mycobacterium tuberculosis bacteria.
- In a negative reaction, there is a very mild swelling or no swelling after two to three days. However, it varies for children and adults affected by the human immunodeficiency virus (HIV).
Positive Result:
- An induration of five to ten millimetres occurs in the site. It indicates positive results for people who recently had organ transplants.
- An individual with a weak immune system due to the human immunodeficiency virus (HIV) gets a positive result.
- Patients taking steroids are more likely to get positive results.
- For the individuals without known risk, a firm swelling of 15 millimetres indicates a positive reaction.
What Do False Positive and False Negative Results Indicate in the Purified Protein Derivative Test?
The false-positive and false-negative results occur in a few medical conditions. It includes;
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The individual with a history of recent Bacillus calmette guerin (BCG) vaccination gets a false-positive reaction.
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To overcome such situations, the medical professional will take chest X-rays and sputum tests to diagnose lung infection.
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The bacterial infection shows increased sputum production. Sputum culture is a painless test and is examined in a laboratory. It is used to identify respiratory tract infections and lung infections.
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The chest X-rays show multiple light areas in both the lungs. It indicates the presence of tuberculosis infection.
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Some patients affected by tuberculosis do not show any results. It is known as a false-negative result.
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Cancer patients and patients undergoing chemotherapy have weak immune systems. They usually get false-negative results.
Who Are the High-Risk Individuals?
In high-risk individuals, the skin reaction shows swelling of more than 10 mm.
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Patients with preexisting diseases like diabetes, renal failure, and intravenous drug users are more prone to tuberculosis infection and the results appear positive.
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People in nursing homes and caretakers of elders are more likely to get infected with tuberculosis patients and show a positive response.
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Infants and children under five years are exposed to the adults affected by tuberculosis.
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The people who are homeless or migrated from the country with severe tuberculosis rates are at higher risk.
Conclusion
The individual who had a positive result in the past should not be tested again. A purified protein derivative test is not a confirmatory test for screening. More tests are performed by the medical professionals to confirm the presence of tuberculosis infection. The medication for tuberculosis is usually prescribed for six to nine months. The patients are kept in direct monitoring by the healthcare professional. If the first protein purified derivative (PPD) test is negative, then the test is repeated after three weeks to check if the results are the same. Consult the physician immediately if the bump turns red or itchy.
