BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuPPD skin testPurified protein derivative standard; TB skin test; Tuberculin skin test; Mantoux testThe PPD skin test is a method used to diagnose silent (latent) tuberculosis (TB) infection. PPD stands for purified protein derivative.TuberculosisPulmonary tuberculosis (TB) is a contagious bacterial infection that involves the lungs. It may spread to other organs.ImageRead Article Now Book Mark Article How the Test is Performed You will need two visits to your health care provider's office for this test.At the first visit, the provider will clean an area of your skin, usually the inside of your forearm. You will get a small shot (injection) that contains PPD. The needle is gently placed under the top layer of skin, causing a bump (welt) to form. This bump usually goes away in a few hours as the material is absorbed.After 48 to 72 hours, you must return to your provider's office (in some cases, this can be done virtually). Your provider will check the area to see if you have had a strong reaction to the test. How to Prepare for the Test There is no special preparation for this test.Tell your provider if you have ever had a positive PPD skin test. If so, you should not have a repeat PPD test, except under unusual circumstances.Tell your provider if you have a medical condition or if you take certain medicines, such as steroids, which can affect your immune system. These situations may lead to inaccurate test results.Tell your provider if you have received the BCG vaccine and if so, when you received it. (This vaccine is only given outside of the United States). How the Test will Feel You will feel a brief sting as the needle is inserted just below the skin surface. Why the Test is Performed This test is done to find out if you have ever come in contact with the bacteria that cause TB. TB is an easily spread (contagious) disease. It most often affects the lungs. The bacteria can remain inactive (dormant) in the lungs for many years. This situation is called latent TB. Most people in the United States who are infected with the bacteria do not have signs or symptoms of active TB. You are most likely to need this test if you:May have been around someone with TB Work in health care Have a weakened immune system, due to certain medicines or disease (such as cancer or HIV/AIDS) CancerCancer is the uncontrolled growth of abnormal cells in the body. Cancerous cells are also called malignant cells.Read Article Now Book Mark Article HIV/AIDSHuman immunodeficiency virus (HIV) is the virus that causes acquired immunodeficiency syndrome (AIDS). When a person becomes infected with HIV, the ...ImageRead Article Now Book Mark Article Normal Results A negative reaction usually means you have never been infected with the bacteria that cause TB. With a negative reaction, the skin where you received the PPD test is not swollen, or the swelling is very small. Interpreting the size of the swelling is different for children, people with HIV, and other high-risk groups.The PPD skin test is not a perfect screening test. A few people infected with the bacteria that cause TB may not have a reaction. Also, diseases or medicines that weaken the immune system may cause a false-negative result. What Abnormal Results Mean An abnormal (positive) result means you have been infected with the bacteria that cause TB. You may need treatment to lower the risk of the disease coming back (reactivation of the disease). A positive skin test does not mean that a person has active TB. More tests must be done to check whether there is active disease. A small reaction (5 mm or more of firm swelling at the site) is considered to be positive in people:Who have HIV/AIDS Who have received an organ transplant Who have a suppressed immune system or are taking steroid therapy (about 15 mg of prednisone per day for 1 month) Who have been in close contact with a person who has active TB Who have changes on a chest x-ray that look like past TB Chest x-rayA chest x-ray is an x-ray of the chest, lungs, heart, large arteries, ribs, and diaphragm.ImageRead Article Now Book Mark Article Larger reactions (10 mm or more) are considered positive in:People with a known negative test in the past 2 years People with diabetes, kidney failure, or other conditions that increase their chance of getting active TB DiabetesDiabetes is a long-term (chronic) disease in which the body cannot regulate the amount of sugar in the blood.ImageRead Article Now Book Mark Article Kidney failureAcute kidney failure is the rapid (less than 2 days) loss of your kidneys' ability to remove waste and help balance fluids and electrolytes in your b...ImageRead Article Now Book Mark Article Health care workers Injection drug users Immigrants who have moved from a country with a high TB rate in the past 5 years Children under age 4 Infants, children, or adolescents who are exposed to high-risk adults Students and employees of certain group living settings, such as prisons, nursing homes, and homeless shelters In people with no known risks of TB, 15 mm or more of firm swelling at the site indicates a positive reaction.People who were born outside the United States who have had a vaccine called BCG may have a false-positive test result. Risks There is a very small risk for severe redness and swelling of the arm in people who have had a previous positive PPD test and who have the test again. Generally, people who have had a positive test in the past should not be retested. This reaction can also occur in a few people who have not been tested before.Open ReferencesReferences Centers for Disease Control and Prevention website. Tuberculosis (TB). About tuberculosis. www.cdc.gov/tb/about/index.html. Reviewed December 19, 2023. Accessed June 25, 2024.Fitzgerald DW, Sterling TR, Haas DW. Mycobacterium tuberculosis. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 249.Rodino KG, Woods GL, Wengenack NL. Mycobacteria. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 59.AllVideoImagesTogTuberculosis in the kidney - illustration Tuberculosis in the kidneyillustrationTuberculosis in the lung - illustration Tuberculosis is caused by a group of organisms, Mycobacterium tuberculosis, M bovis, M africanum and a few other rarer subtypes. Tuberculosis usually appears as a lung (pulmonary) infection. However, it may infect other organs in the body. Recently, antibiotic-resistant strains of tuberculosis have appeared. With increasing numbers of immunocompromised individuals with AIDS, and homeless people without medical care, tuberculosis is seen more frequently today. (Image courtesy of the Centers for Disease Control and Prevention.)Tuberculosis in the lungillustrationPositive PPD skin test - illustration The positive immunologic response to PPD antigen is seen here. The size of the papule is over 2 cm in diameter.Positive PPD skin testillustrationPPD skin test - illustration The purified protein derivative is an antigen (a substance that stimulates the immune system to eliminate or fight foreign substances in the body), which is injected under the skin in the forearm. After 48 to 72 hours the injection site is evaluated by a physician. This skin test helps determine if a person has ever been infected by the microorganism that causes tuberculosis. PPD skin testillustrationTuberculosis in the kidney - illustration Tuberculosis in the kidneyillustrationTuberculosis in the lung - illustration Tuberculosis is caused by a group of organisms, Mycobacterium tuberculosis, M bovis, M africanum and a few other rarer subtypes. Tuberculosis usually appears as a lung (pulmonary) infection. However, it may infect other organs in the body. Recently, antibiotic-resistant strains of tuberculosis have appeared. With increasing numbers of immunocompromised individuals with AIDS, and homeless people without medical care, tuberculosis is seen more frequently today. (Image courtesy of the Centers for Disease Control and Prevention.)Tuberculosis in the lungillustrationPositive PPD skin test - illustration The positive immunologic response to PPD antigen is seen here. The size of the papule is over 2 cm in diameter.Positive PPD skin testillustrationPPD skin test - illustration The purified protein derivative is an antigen (a substance that stimulates the immune system to eliminate or fight foreign substances in the body), which is injected under the skin in the forearm. After 48 to 72 hours the injection site is evaluated by a physician. This skin test helps determine if a person has ever been infected by the microorganism that causes tuberculosis. PPD skin testillustrationA Closer Look Psoriasis-In-Depth(In-Depth) Tests for PPD skin test PPD skin testRelated Information Antigen(Special Topic)Pulmonary tuberculosis(Condition) Review Date: 12/31/2023 Reviewed By: Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. Editorial update 06/25/2024. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. 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PPD skin testPurified protein derivative standard; TB skin test; Tuberculin skin test; Mantoux testThe PPD skin test is a method used to diagnose silent (latent) tuberculosis (TB) infection. PPD stands for purified protein derivative.TuberculosisPulmonary tuberculosis (TB) is a contagious bacterial infection that involves the lungs. It may spread to other organs.ImageRead Article Now Book Mark Article How the Test is Performed You will need two visits to your health care provider's office for this test.At the first visit, the provider will clean an area of your skin, usually the inside of your forearm. You will get a small shot (injection) that contains PPD. The needle is gently placed under the top layer of skin, causing a bump (welt) to form. This bump usually goes away in a few hours as the material is absorbed.After 48 to 72 hours, you must return to your provider's office (in some cases, this can be done virtually). Your provider will check the area to see if you have had a strong reaction to the test. How to Prepare for the Test There is no special preparation for this test.Tell your provider if you have ever had a positive PPD skin test. If so, you should not have a repeat PPD test, except under unusual circumstances.Tell your provider if you have a medical condition or if you take certain medicines, such as steroids, which can affect your immune system. These situations may lead to inaccurate test results.Tell your provider if you have received the BCG vaccine and if so, when you received it. (This vaccine is only given outside of the United States). How the Test will Feel You will feel a brief sting as the needle is inserted just below the skin surface. Why the Test is Performed This test is done to find out if you have ever come in contact with the bacteria that cause TB. TB is an easily spread (contagious) disease. It most often affects the lungs. The bacteria can remain inactive (dormant) in the lungs for many years. This situation is called latent TB. Most people in the United States who are infected with the bacteria do not have signs or symptoms of active TB. You are most likely to need this test if you:May have been around someone with TB Work in health care Have a weakened immune system, due to certain medicines or disease (such as cancer or HIV/AIDS) CancerCancer is the uncontrolled growth of abnormal cells in the body. Cancerous cells are also called malignant cells.Read Article Now Book Mark Article HIV/AIDSHuman immunodeficiency virus (HIV) is the virus that causes acquired immunodeficiency syndrome (AIDS). When a person becomes infected with HIV, the ...ImageRead Article Now Book Mark Article Normal Results A negative reaction usually means you have never been infected with the bacteria that cause TB. With a negative reaction, the skin where you received the PPD test is not swollen, or the swelling is very small. Interpreting the size of the swelling is different for children, people with HIV, and other high-risk groups.The PPD skin test is not a perfect screening test. A few people infected with the bacteria that cause TB may not have a reaction. Also, diseases or medicines that weaken the immune system may cause a false-negative result. What Abnormal Results Mean An abnormal (positive) result means you have been infected with the bacteria that cause TB. You may need treatment to lower the risk of the disease coming back (reactivation of the disease). A positive skin test does not mean that a person has active TB. More tests must be done to check whether there is active disease. A small reaction (5 mm or more of firm swelling at the site) is considered to be positive in people:Who have HIV/AIDS Who have received an organ transplant Who have a suppressed immune system or are taking steroid therapy (about 15 mg of prednisone per day for 1 month) Who have been in close contact with a person who has active TB Who have changes on a chest x-ray that look like past TB Chest x-rayA chest x-ray is an x-ray of the chest, lungs, heart, large arteries, ribs, and diaphragm.ImageRead Article Now Book Mark Article Larger reactions (10 mm or more) are considered positive in:People with a known negative test in the past 2 years People with diabetes, kidney failure, or other conditions that increase their chance of getting active TB DiabetesDiabetes is a long-term (chronic) disease in which the body cannot regulate the amount of sugar in the blood.ImageRead Article Now Book Mark Article Kidney failureAcute kidney failure is the rapid (less than 2 days) loss of your kidneys' ability to remove waste and help balance fluids and electrolytes in your b...ImageRead Article Now Book Mark Article Health care workers Injection drug users Immigrants who have moved from a country with a high TB rate in the past 5 years Children under age 4 Infants, children, or adolescents who are exposed to high-risk adults Students and employees of certain group living settings, such as prisons, nursing homes, and homeless shelters In people with no known risks of TB, 15 mm or more of firm swelling at the site indicates a positive reaction.People who were born outside the United States who have had a vaccine called BCG may have a false-positive test result. Risks There is a very small risk for severe redness and swelling of the arm in people who have had a previous positive PPD test and who have the test again. Generally, people who have had a positive test in the past should not be retested. This reaction can also occur in a few people who have not been tested before.Open ReferencesReferences Centers for Disease Control and Prevention website. Tuberculosis (TB). About tuberculosis. www.cdc.gov/tb/about/index.html. Reviewed December 19, 2023. Accessed June 25, 2024.Fitzgerald DW, Sterling TR, Haas DW. Mycobacterium tuberculosis. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 249.Rodino KG, Woods GL, Wengenack NL. Mycobacteria. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 59.