MedicineNet.com

About Us | Privacy Policy | Site Map
February 8, 2012

Tuberculosis Skin Test
(PPD Skin Test)

Medical Author:
Medical Editor:

What is the tuberculosis skin test?

The tuberculosis skin test is a test used to determine if someone has developed an immune response to the bacterium that causes tuberculosis (TB). This response can occur if someone currently has TB, if they were exposed to it in the past, or if they received the BCG vaccine against TB (which is not performed in the U.S.). The World Health Organization estimates that 2 billion people worldwide have latent TB, while around 3 million people worldwide die of TB each year. The tuberculosis skin test is also known as the tuberculin test or PPD test.

The tuberculin skin test is based on the fact that infection with M. tuberculosis bacterium produces a delayed-type hypersensitivity skin reaction to certain components of the bacterium. The components of the organism are contained in extracts of culture filtrates and are the core elements of the classic tuberculin PPD (also known as purified protein derivative). This PPD material is used for skin testing for tuberculosis. Reaction in the skin to tuberculin PPD begins when specialized immune cells, called T cells, which have been sensitized by prior infection, are recruited by the immune system to the skin site where they release chemical messengers called lymphokines. These lymphokines induce induration (a hard, raised area with clearly defined margins at and around the injection site) through local vasodilation (expansion of the diameter of blood vessels) leading to fluid deposition known as edema, fibrin deposition, and recruitment of other types of inflammatory cells to the area.

An incubation period of two to 12 weeks is usually necessary after exposure to the TB bacteria in order for the PPD test to be positive. Anyone can have a TB test, and it can be given to infants, pregnant women, or HIV-infected people with no danger. It is only contraindicated in people who have had a severe reaction to a previous tuberculin skin test.



Patient Discussions

Viewers share their comments

Tuberculosis Skin Test (PPD Skin Test) - Symptoms Question: What were the symptoms and signs of your tuberculosis infection?

MedicineNet Doctors

Suggested Reading on Tuberculosis Skin Test (PPD Skin Test) by Our Doctors

  • Related Diseases & Conditions

    • Rheumatoid Arthritis
      • Rheumatoid arthritis is an autoimmune disease that causes chronic inflammation of the joints, the tissue around the joints, as well as other organs in the body. Because it can affect multiple other organs of the body, rheumatoid arthritis is referred to as a systemic illness and is sometimes called rheumatoid disease.
    • Crohn's Disease
      • Crohn's disease is a chronic inflammatory disease, primarily involving the small and large intestine, but which can affect other parts of the digestive system as well. Abdominal pain, diarrhea, vomiting, fever, and weight loss are common symptoms.
    • Diabetes (Type 1 and Type 2)
      • Diabetes mellitus is a chronic condition characterized by high levels of sugar (glucose) in the blood. The two types of diabetes are referred to as type 1 (insulin dependent) and type 2 (non-insulin dependent). Symptoms of diabetes include increased urine output, thirst, hunger, and fatigue. Treatment of diabetes depends on the type.
    • Tuberculosis
      • Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis bacteria. Symptoms include weakness, fever, weight loss, night sweats and in worse cases, chest pain, shortness of breath, and coughing up blood. A person with an active infection (a positive TB skin test, abnormal chest x-ray and TB bacteria in their sputum) requires treatment with izoniazid, rifampin, ethambutol and pyrazinaide.
    • Cancer
      • Cancer is a disease caused by an abnormal growth of cells, also called malignancy. It is a group of 100 different diseases, and is not contagious. Cancer can be treated through chemotherapy, a treatment of drugs that destroy cancer cells.
    • Hypertensive Kidney Disease
      • High blood pressure can damage the kidneys and is one of the leading causes of kidney failure (end-stage renal kidney disease). Kidney damage, like hypertension, can be unnoticeable and detected only through medical tests. If you have kidney disease, you should control your blood pressure. Other treatment options include prescription medications.
    • Extensively Drug-Resistant Tuberculosis (XDR TB)
      • Extensively drug-resistant tuberculosis (XDR TB) is a rare form of multidrug-resistant tuberculosis (MDR TB) that's transmitted when TB germs are expelled into the air by sneezing, speaking, singing, or coughing.
    • Disease Prevention in Women
      • Disease prevention in women includes screening tests that are a basic part of prevention medicine. All screening tests are commonly available through your general doctor. Some specialized tests may be available elsewhere.
  • Medications

  • Procedures & Tests

  • Pictures, Images & Illustrations

  • Doctor's & Expert's Views

  • Health News

  • Health Features

Women's Health

Find out what women really need.



Symptom Checker: Your Guide to Symptoms & Signs: Pinpoint Your Pain



Tuberculosis Skin Test (PPD Skin Test)

Diabetes Facts

  • Diabetes is a chronic condition associated with abnormally high levels of sugar (glucose) in the blood.
  • Insulin produced by the pancreas lowers blood glucose.
  • Absence or insufficient production of insulin causes diabetes.
  • The two types of diabetes are referred to as type 1 (insulin dependent) and type 2 (non-insulin dependent).
  • Symptoms of diabetes include increased urine output, thirst and hunger as well as fatigue.
  • Diabetes is diagnosed by blood sugar (glucose) testing.
  • The major complications of diabetes are both acute and chronic.

    • Acutely: dangerously elevated blood sugar, abnormally low blood sugar due to diabetes medications may occur.
    • Chronically: disease of the blood vessels (both small and large) which can damage the eye, kidneys, nerves, and heart may occur

  • Diabetes treatment depends...

Read the Diabetes (Type 1 and Type 2) article »







Use Pill Finder Find it Now

Pill Identifier on RxList

  • quick,
    easy,
    pill identification

Find a Local Pharmacy

  • including
    24 hour
    pharmacies