Tuberculosis is a highly contagious disease caused due to the presence of TB bacteria in the air. These TB bacterias will affect the body parts such as lungs and lymph nodes. However, active TB cause symptoms like weak immunity system, coughing, high fever, chills and sudden body loss.
Moreover, it also affects attacks on various organs in the body and causes tissues to die. So there are two tests: a skin test and a blood test that help you to diagnose tuberculosis. Having a checkup will help you to treat TB and know with what type of medication. Here in this article, we are going to show what does a positive TB test look like.
What Does a Positive TB Skin Test Look Like?
TB bacteria present in the air is the reason that can cause TB. It is also referred to in short as a highly contagious disease. Tuberculosis affects other parts of the body like the lymph nodes, and it also impacts the lungs.
Active TB will cause symptoms such as coughing, weakened immune system, malaise, body aches, night sweats, high fever, chills, and sudden weight loss. Active tuberculosis can be deadly as it attacks various organs in the body and causes tissue to die.
Mainly this disease is caused by an infection of bacteria called Mycobacterium tuberculosis. Mycobacterium tuberculosis can result in either active TB disease or latent TB infection. Latent TB shows no signs or symptoms. However, latent TB disease can become active TB disease.
However, active tuberculosis disease treated with six to nine months of meditation. And usually, latent tuberculosis disease is treated to prevent future active disease.
TB Blood Test vs Skin Test
A blood test and a skin test are the two types of TB test that help you to figure out whether you have TB or not. But both of these tests will not show you whether you are suffering from latent TB or active TB. After testing the doctors will decide whether you should treat with what type of meditation.
During a TB skin test
A TB skin test is also known as a Mantoux tuberculin skin test. TST is well-tolerated, and people rarely have rebutted reactions to it.
Mantoux tuberculin skin test is in two parts:
First part :
Firstly, when you visit a clinic, usually in your forearm under the skin, a tiny amount of tuberculin is injected. Tuberculin is a Sterile extract purified protein derivative. And purified protein derivative is made from the bacteria that cause TB.
After receiving the PPD injection, a small pale bump will form on the surface.
Second part :
After 48 to 72 hours later, the second phase of the test takes place. It is the time when a doctor will look at how your skin reacted to tuberculin. Then the doctor will examine your skin reaction and determine if you have infected with TB or not.
And starting after 72 hours is too long, so, therefore, you have to start with a new test and a new injection.
If your first skin test results are negative, then the doctor will ask you to perform your test again after one to three weeks to ensure that the results remain the same. Below we are going to discuss what does a positive TB test look like.
How To Identify Infection?
If you infected with Mycobacterium tuberculosis (Mtb), by 48 to 72 hours, the skin starts to swell and harden around the site of the injection.
The swell and harden area is also known as a bump, or induration clinically will turn red. The results are not determined based on the size and redness of the induration.
Perpendicular to the axis between your hand and elbow, you must measure the induration across the forearm.
Some standards of measurement are:-
Here are some standards of measurement that help you to know whether you are diagnosed with a positive tuberculosis test. However, these measurements will help you figure out what a positive TB test looks like.
Less than 5mm
If the redness measures less than 5mm, then you are not diagnose with TB.
At least 5mm
If the redness measures at least 5mm, then the result will be positive, if you had recent contact with someone having TB, you are HIV positive, and you previously have tuberculosis.
At least 10mm
If the reaction measures at least 10mm, then the result will be positive, if you immigrated from a country having a high incidence of TB, you are working with high-risk settings, or you live in a high-risk environment.
15mm or more
If the redness measures 15mm or more, then you are diagnosed with tuberculosis.
Recognizing the results of the TB test
The doctor will prescribe you medications to clear up the infection if you have a positive TB test result.
If you have a positive skin test, then the doctor will recommend you TB blood test for confirmation. However, a study shows that the blood test is more accurate than the TB skin test. So there can be a possibility that you have a positive TB skin test and a negative blood test.
False Positive Result
If you have received the bacillus Calmette-Guérin (BCG) vaccine, then you will get a false-positive result.
Few reasons that show a false positive result are:-
- Not having proper administration of the test.
- Not having an accurate interpretation of your test results.
False Negative Result
You can even get a negative result if you infected with TB. Inaccurate interpretation and not having proper administration of the test could lead to a false-negative test result.
Some immune system conditions such as an organ transplant could lead to a false-negative skin test.
If you exposed to TB in the past few weeks, then your results will not be positive. Even if the infant is affected by TB, may not always have a positive skin test.
If your test result appears to negate, but you think that you exposed to TB, then a second skin test is a must or a blood test.
Symptoms of TB
If you have active TB disease, you will only have symptoms. You will not produce any noticeable symptoms if you have a TB infection.
There are many symptoms of TB infection, but the cough is one of the most common symptoms of TB. Other signs of TB infection are:- fatigue, fever, night sweats, weight loss, decreased appetite all are the symptoms of TB infection.
It is vital to get tested because these symptoms can occur in many conditions. Even a negative test may be helpful for your doctor to find other causes for your symptoms.
Next Steps After A Positive skin test
A chest X-ray must be helpful if a positive skin test appears. It helps to decide the difference between active TB disease and latent TB infection. White spots would indicate your doctor that your immune system is responding to bacteria.
TB disease can also cause changes in your lungs. Your doctor may decide whether a CT scan would use instead of an X-ray because a CT scan is a much better option.
Your doctor may advise you to test your sputum to identify that TB is present or not. When you cough you produce a mucus, that is called sputum. A lab test will help to recognize the type of TB bacteria. It could be helpful for doctors to decide which medication to prescribe.
If you are suffering from TB, then for a full recovery, you must follow the prescribed medications recommended by your doctor.
What is a TB blood test?
TB blood test is known as interferon-gamma release assays that help to measure your response to TB antigens. However, you don’t need any other visit if you have a blood test. Moreover, if your tuberculosis is active, then you will get other tests to see.
The doctor will draw a small amount of blood and send it to the laboratory. Then if your blood test results negative, there are no TB germs in your body. On the other hand, if your blood test is positive, then you will have TB germs in your body.
Most of the time, people having positive TB blood tests have latent TB infection. So your doctor must examine you and do a chest x-ray. However, if you have active TB disease or latent TB infection, then you may need other tests.
So here we have shown what does a positive TB test look like. However, tuberculosis is a contagious disease that attacks your lungs and destroys your immunity system. TB is treatable if you have the TB test properly, take all medication and follow doctor’s recommendations correctly.