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Positive tuberculin test

Positive TB Skin Test Result: What Does It Mean? New

How do you know if you test positive for tuberculosis? A skin test is the only way to tell if you have TB infection. The test is positive if a bump about the size of a pencil eraser or bigger appears on your arm. This bump means you probably have TB infection. Other tests can show if you have TB disease A positive blood test indicates that a person is either currently infected or has been infected with TB bacteria in the past. A follow-up chest x-ray or sputum culture may need to be completed to confirm a positive result from either the skin or the blood test. Here are some potential explanations for a positive TB test Tuberculin Skin Test (also known asMantoux Test, PPD Test or Mendel-Mantoux Test or Pirquet test) is a screening test done on the skin for diagnosis of Tuberculosis (TB) using Purified Protein Derivative (PPD). A Positive Tuberculin skin test is an example of type 4 hypersensitivity reaction (A delayed hypersensitivity Skin reaction) that is, it is cell mediated immunity; which is based on the immune response of the body to the Purified Protein Derivative (PPD) Type of tuberculin test did not modify these results. In 18 studies involving 1,169,105 subjects, the absolute prevalence of false-positive TST from NTM cross-reactivity ranged from 0.1% to 2.3% in different regions. Conclusions: The effect on TST of BCG received in infancy is minimal, especially > or =10 years after vaccination. BCG received after infancy produces more frequent, more persistent and larger TST reactions

Positive vs

Testing & Diagnosis TB CD

Positive PPD Skin test If the infection risk is very high, the PPD test need not be repeated. The positive PPD test is usually followed by TB symptom assessment, physical exam, and chest radiograph A positive TB blood test result means you probably have TB germs in your body. Most people with a positive TB blood test have latent TB infection. To be sure, your doctor will examine you and do a chest x-ray. You may need other tests to see if you have latent TB infection or active TB disease Though this child had a positive Mantoux test it does not suggest active tuberculosis. The child also had a positive Mantoux test 1 year ago and was treated for latent TB at that time adequately. A positive mantoux currently could suggest past TB infection, positivity due to previous BCG vaccination or even infection due to atypical mycobacteria. Thus, one cannot interpret mantoux test in this child

Search Results. 500 results found. Showing 1-25: ICD-10-CM Diagnosis Code R76.11 [convert to ICD-9-CM] Nonspecific reaction to tuberculin skin test without active tuberculosis. Nonspecific reaction to skin test w/o active tuberculosis; False positive purified protein derivative; Mantoux: positive; Tuberculin skin test false positive; Tuberculin. A positive tuberculin skin test does not mean you have contagious (active) TB. The test cannot tell whether you have active or inactive (latent) TB. It also cannot tell the difference between a TB infection and a TB vaccination (BCG vaccination) Background: When determining eligibility for isoniazid preventive therapy of human immunodeficiency virus (HIV)-infected patients, the cutoff value of the tuberculin skin test (TST) is often reduced from an induration of 10 mm in diameter to one of 5 mm in diameter to compensate for loss of sensitivity. The effectiveness of this reduction depends on the underlying mechanism: a gradual decrease in skin test responsiveness with decreasing immunocompetence or an all-or-nothing switch to.

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 The tuberculin skin test is the most frequently used method for detecting asymptomatic latent tuberculosis infection. There is growing interest in other diagnostic tests for latent infection that might be simpler to administer, but the tuberculin skin test remains the preferred modality because of its ease of use and low cost. The decision to perform an annual test or a single test depends on. Tuberculin skin test positive ICD-10-CM R76.11 is grouped within Diagnostic Related Group(s) (MS-DRG v 39.0): 177 Respiratory infections and inflammations with mc

Tuberculosis (TB) Fact Sheets- Tuberculin Skin Testin

  1. The TB skin test, also known as the Mantoux tuberculin skin test, is the most common way doctors diagnose tuberculosis. They'll inject a tiny amount of fluid called tuberculin just below the.
  2. Tuberculin Skin Test (TST) The Tuberculin Skin Test (TST), also known as a Mantoux test, is used to assess whether a person has been infected with the tuberculosis (TB) bacteria. The TST is primarily used to diagnose TB infection. This is when the TB bacteria is in the body but the person is not experiencing any symptoms suggestive of TB disease
  3. In such cases of a false-negative or a false-positive reaction skin test may have to be repeated again along with other investigations either support or rule out the diagnosis or Tuberculosis. The reaction of the body to a dose of tuberculin injected intradermally is a type of delayed hypersensitivity response
  4. istration of the skin test requires large amounts of training, supervision, and practice
  5. ation, chest X-ray, and other lab tests

M. DePietro Chest x-rays are used to help diagnose tuberculosis. Positive tuberculosis skin test results do not necessarily indicate a person has active tuberculosis or is contagious. Usually, after a person comes back with a positive purified protein derivative skin test, additional testing is needed to determine if active tuberculosis is present Your GP may suggest having a test when you register as a patient. Mantoux test The Mantoux test is a widely used test for latent TB. It involves injecting a small amount of a substance called PPD tuberculin into the skin of your forearm. It's also called the tuberculin skin test (TST) The result depends on the size of the raised, hard area or swelling. The diameter of hard skin thickening is recorded in millimeters. Positive PPD skin test or abnormal (more than 5 mm induration): This means the person's body was infected with tuberculosis bacteria. Abnormal tests may take weeks to subside and can leave a mark or scar The standard recommended tuberculin test is the Mantoux test, which is administered by injecting a 0.1 mL of liquid containing 5 TU (tuberculin units) PPD (purified protein derivative)into the top layers of skin of the forearm. Skin tests should be read 48-72 hours after the injection A positive TB skin test is when the Mantoux tuberculin skin test (TST) indicates that a person has the tuberculosis bacterium, Mycobacterium tuberculosis in their body based on the appearance of the skin prick test after 48 to 72 hours

A positive TB skin test means that you are infected with the bacteria, Mycobacterium tuberculosis, and it is present in your body. TB bacteria live in the bodies of most infected people in an inactive form and do not cause any symptoms of disease; this condition is referred to as Latent TB Infection (LTBI) A positive TB blood test result means you probably have TB germs in your body. Most people with a positive TB blood test have latent TB infection. To be sure, your doctor will examine you and do a chest x-ray. You may need other tests to see if you have latent TB infection or active TB disease.. What is a positive QuantiFERON TB Gold test? If your TST (Mantoux) or Quantiferon blood test. What is the ICD 10 code for positive PPD? R76. 11 is a billable ICD code used to specify a diagnosis of nonspecific reaction to tuberculin skin test without active tuberculosis. A 'billable code' is detailed enough to be used to specify a medical diagnosis. Click to read in-depth answer A tuberculin test reading of >=10 mm is considered as positive results in the following individuals 1) Immigrants (Less than 5 years) who have come from countries with high prevalence of TB 2) HIV negative injection drug user

What Does a Positive TB Test Look Like? (With Pictures and

Test Overview. A tuberculin skin test (also called a Mantoux tuberculin test) is done to see if you have ever been exposed to tuberculosis (TB). The test is done by putting a small amount of TB protein (antigens) under the top layer of skin on your inner forearm.If you have ever been exposed to the TB bacteria (Mycobacterium tuberculosis), your skin will react to the antigens by developing a. In a study conducted in 2007, the prevalence of positive tuberculin skin test was found to be 22% in Sweden . A prospective study of serial tuberculin skin testing performed on 642 patients from the chronic care wards of a Veterans Administration Hospital revealed a positive test in 23.6% [ 20 ]

What Does a Positive TB Test Look Like? - Health Center

To read a tuberculosis skin test, start by going to the doctor for a test, which involves an injection that will cause a welt on your arm. If the welt is a soft bump, the results are likely negative. However, if it's a hard, dense, raised formation, the results may be positive The test involves injecting a small amount of fluid containing certain components of the TB bacterium under the skin. This will cause your immune system to recognize the injected solution as a threat, causing a skin reaction. The degree of the skin's response will determine if the results are positive or negative A: A tuberculin test is a skin test done to check the presence of cell mediated immunity of an individual towards the tuberculoprotein (PPD). A positive test only indicates that the person has been exposed to Mycobacterium tuberculosis in the past and has developed cell mediated immunity. It is not a test to diagnose active tuberculosis showing positive tuberculin reactions should be considered positive by current public health guidelines and referred for further medical evaluation. (8) (10) The repeated testing of uninfecte 32.4K. Description. Tuberculin Skin Test (Positive Mantoux Test) Result, Reading and Interpretation #Diagnosis #Tuberculosis #LatentTB #Tuberculin #SkinTest #TST #Interpretation #Induration #Thresholds #Diameters #PPD ** GrepMed Recommended Text: Bates' Guide to Physical Examination and History Taking - https://amzn.to/2Z6LYmf

Mantoux tuberculin skin test and causes of positive

Tuberculosis Skin Test (PPD): Reading, Results, Side

  1. Findings of cross-sectional studies indicate a better diagnostic accuracy of interferon-γ release assays over the tuberculin skin test. The critical issue is that in low-incidence countries, the positive and negative predictive values of any of immunodiagnostic tests were very poor. A targeted testing process involving analysis of TB risk.
  2. Here are a number of highest rated Positive Tuberculin Skin Test pictures upon internet. We identified it from honorable source. Its submitted by giving out in the best field. We take this nice of Positive Tuberculin Skin Test graphic could possibly be the most trending subject similar to we portion it in google plus or facebook
  3. es if you have tuberculosis (TB).. TB is a serious infection, usually of the.
  4. A false-positive tuberculin test result. February 2000; Canadian Medical Association Journal (between 1951-60 nearly 150 million people had been tuberculin tested and 54 million have been.
  5. A tuberculin reaction test is classified as positive depending on the diameter of the induration in combination with some patient-specific risk factors. In a normal, healthy individual with the properly functioning immune system, an induration greater than or equal to 15 mm is considered a positive skin test

Tuberculin used for the skin test is also known as purified protein derivative, PPD. The TST is sometimes called PPD test or Mantoux test. BCG vaccination induces a state of hypersensitivity which can result in a false positive TST, such that the average diameter 1 year after BCG vaccination is 10 mm, with extremes ranging from 4 to 20 mm Once positive, a TST reaction will usually remain positive for life and the skin reaction to subsequent tuberculin skin tests may become increasingly severe. What does the test result mean? A healthcare practitioner will interpret a tuberculin skin test result by looking at the injection site on the person's forearm at 48 or 72 hours (in most. pulmonary TB will have a positive tuberculin skin test (TST).2 Age, proximity of exposure, malnutrition, household crowding and the contact's Bacille Calmette-Guérin (BCG) vaccination scar status have been found to influence TST positivity among childhood * Corresponding author. Laboratory of Pediatric Infectious Diseases, Radbou

Mantoux test - Wikipedi

presupposes a decision to treat if the test is positive. • There are two accepted tests for identification of LTBI: the tuberculin skin test (TST) and the interferon gamma release assay (IGRA). • When interpreting a positive TST, it is important to consider much more than simply the size of the reaction 3.1. Intradermal tuberculin skin test In many facilities the diagnosis of tuberculosis is based upon the intradermal in vivo tuberculin skin test (TST) using mammalian old tuberculin (MOT) or purified protein derivates (PPD). The tuberculin is injected intradermally into an eyelid near edge or into it

Positive skin tests with indurations of >15 mm are more likely to be the result of tuberculous infection than of BCG vaccination. Conclusions: In subjects without active tuberculosis, immunisation with BCG significantly increases the likelihood of a positive tuberculin skin test Mantoux test positive symptoms are detected in a healthy person if the induration is greater than or equal to 15mm. The Mantoux test positive is absolute if blisters are present while interpreting. Here is an indicative reference range that is used by the healthcare professionals to interpret the results of the Mantoux test measurement for results Tuberculin Skin Test (TST) Quick Reference Guide for Health Care Providers Reading the Tuberculin Skin Test (TST) Must be read by a trained health care professional. Ensure the patient has returned within 48-72 hours of administration. 1. Gather supplies • Caliper or flexible ruler, pen and documentation record 2. Inspect TST sit 8. Vinton P, Mihrshahi S, Johnson P, Jenkin GA, Jolley D, Biggs BA. Comparison of QuantiFERON-TB Gold In-Tube Test and tuberculin skin test for identification of latent Mycobacterium tuberculosis infection in healthcare staff and association between positive test results and known risk factors for infection

The tuberculin skin test (TST) has many limitations, including difficulty in administration and interpretation, the need for a return visit by the patient, and false-positive results caused by cross-reaction with Mycobacterium bovis-bacille Calmette-Guerin vaccines and many nontuberculous mycobacteria ️ Patreon: https://www.patreon.com/USMLEpass My Courses:https://www.udemy.com/user/ahmed-elalim-2 My Apps:https://play.google.com/store/apps/developer?i.. The tuberculosis (TB) blood test, also called an Interferon Gamma Release Assay or IGRA, is a way to find out if you have TB germs in your body. The TB blood test can be done instead of a TB skin test (Mantoux). Most people with a positive TB blood test have latent TB infection These tests require only one office visit. A blood test might be useful if you're at high risk of TB infection but have a negative response to the skin test, or if you've recently received the BCG vaccine. Imaging tests. If you've had a positive skin test, your doctor is likely to order a chest X-ray or a CT scan

Mantoux test and its interpretatio

  1. e the prevalence of positive tuberculin skin test (TST) among HCWs in a highly endemic area for TB in Iran, namely Zahedan, the capital of Sistan and Baluchestan.
  2. Of the 276 contacts of the child whom we tested, 56 (20 percent) had a positive tuberculin skin test (induration of at least 10 mm), including 3 of the child's 4 household members, 16 of his 24.
  3. This test has almost 100% specificity and sensitivity in acid-fast bacilli positive smears, with results provided within a few days (and potentially on the same day).While a negative nucleic acid amplification test of acid-fast bacilli almost excludes tuberculosis, the test can rarely be falsely negative in pulmonary tuberculosis . Sputum smear.
Tuberculin Skin Test Movie 2

need to ever have another TB test, as once the TB skin test is positive, it is positive for life. When you complete a course of treatment with INH for LTBI, Health Services will provide you with a card/letter which documents your past history of a positive TB skin test or postive TB blood test, and your treat-ment A positive tuberculin skin test or QuantiFERON®-TB Gold test only tells that a person has been infected with TB germs. It does not tell whether or not the person has progressed to TB disease. Other tests, such as a chest x-ray and a sample of sputum, are needed to see whether the person has TB disease

What is the ICD 10 code for positive TB test

Bovine Tuberculosis - Testing and examining bTB-positive animals. Bovine Tuberculosis (bTB) is an infectious disease of cattle. It is one of the most significant animal health challenges that England faces today, costing taxpayers more than £100 million each year. In 2020 alone, more than 27,000 cattle had to be slaughtered to curb its spread Caudal-fold tuberculin test (CFT): an intradermal infection of 0.1 mL of USDA purified protein derivative (PPD) tuberculin into either side of the caudal fold with reading by visual observation and palpation. The PPD extract is from. A 33-year-old soldier has recent weight loss, night sweats, fever, and cough Very bad dizziness or passing out. Irritation has happened where this medicine (tuberculin tests) was given. Rarely, tissue damage has happened. Tell your nurse if you have any burning, color changes, pain, skin breakdown, or swelling where this medicine (tuberculin tests) was given

Tuberculin skin test (TST) reaction diameters among 991 patients with smear-positive tuberculosis in 6 Tanzanian hospitals, by HIV infection status. The sensitivity of the TST, based on the crude distribution among HIV-uninfected patients at cutoff values of 15, 10, and 5 mm, was 66.7%, 91.1%, and 95.2% ( figure 2 ) If TST was the initial test, boosting could be a factor if the result of the repeat test is positive. When a tuberculin skin test or interferon gamma release assay is indicated for medical care: The decision as to whether a TST or IGRA that is being done for. a positive TB skin test and/or interferon-gamma release assay, and are otherwise without any signs or symptoms of active disease What are the two main tests used in latent TB? - PPD Skin Test (aka tuberculin skin test (TST), Mantoux test Background Patients with prior positive tuberculin skin test (TST) results may benefit from prophylaxis after repeat exposure to infectious tuberculosis (TB). Objective To evaluate factors associated with active TB disease among persons with prior positive TST results named as contacts of persons with infectious TB. Design Population-based retrospective cohort study. Participants A total of. Main Outcome Measure Tuberculin skin test result. Results Using generalized estimating equations to build a predictive model, 7 variables were found to significantly predict a positive tuberculin skin test result among contacts of an active TB case. Further testing showed this model to have a sensitivity, specificity, and positive predictive.

Positive TB test: Am I sick? Go Ask Alice

higher positive predictive value in high-prevalence popu-lations (9). Among children with a 1% rate of TB infection, the positive predictive value is <10%. Thus, >90% of pos-itive reactions are false positives (10). Since no test can distinguish false positives from true positives, all persons with positive TST results must be evaluated and. The Mantoux tuberculin skin test (TST) or the TB blood test can be used to test for M. tuberculosis infection. Additional tests are required to confirm TB disease. The Mantoux tuberculin skin test is performed by injecting a small amount of fluid called tuberculin into the skin in the lower part of the arm positive tuberculin test and risk of infection in healthcare professionals, who work into upright buildings where a TB reference clinic is located. Patients and Methods This is a transversal, prospective, and descrip-tive study, developed between March 2006 an 2b. is the veteran undergoing treatment or has he or she completed treatment for a tb condition, including active tb, positive skin test or laboratory evidence of tb (positive quantiferon-tb gold test) without active disease? 2c. list medications currently or previously used for treatment of tb condition: yes no. if completed, date of completion The tuberculin skin test involves having a small amount of liquid, called tuberculin, injected into the very top layer of the skin on your forearm. This is done with a small needle and syringe. The test, which is done by specially trained laboratory technicians, does not contain live bacteria and cannot cause TB

Tuberculin Skin Test (Positive Mantoux Test) Result

The tuberculin test or PPD (purified protein derivative) test are other names for the tuberculosis skin test. For those whose sleep is light you can consider take Circadin, is a medicine that is used to treat jetlag and to adjust an irregular sleep pattern, the most popular buy circadin from ukmeds.co.uk Testing for Tuberculosis infection positive skin test reaction. But they may develop TB disease later in life if they do not receive preventive therapy. Tuberculosis Disease is an illness in which TB bacteria are multiplying and attacking different parts of the body. The symptoms of TB disease include weakness, weight loss, fever, no. During a PPD (Mantoux) test, tuberculin antigen is placed intradermally. A positive response, as denoted by induration, blister formation, or hypersensitivity, represents a type IV (delayed type) hypersensitivity reaction. 1 Type IV reactions involve sensitized T lymphocytes that are recruited to the PPD site where cytokines, such as interferon. A positive reaction can usually be seen for about 1 week. A positive tuberculin skin test doesn't mean you have contagious (active) TB. The test can't tell whether you have active or inactive (latent) TB. It also can't tell the difference between a TB infection and a TB vaccination (BCG vaccination)

False-positive tuberculin skin tests: what is the absolute

Based on the sensitivity and specificity of the tuberculin skin test and the prevalence of TB in different groups, three cut-off levels of induration have been recommended by the American Thoracic Society and other study groups for defining a positive tuberculin reaction: greater than 5 mm, [greater than or equal to]10 mm, and [greater than or equal to]15 mm of induration Tuberculin (also called purified protein derivative or PPD) is the solution used to administer the test. The preferred term for the test is tuberculin skin test, or TST. People who have been vaccinated with Bacille Calmette-Guérin (BCG) should not be exempted from TB skin testing unless they have a documented positive result from a prior test Chest X-rays - Individuals with symptoms of active pulmonary tuberculosis or those with a new positive test for TB infection will need to obtain a chest x-ray. If abnormal findings are present in the x-ray, further testing will be required before employment clearance can be provided Negative Positive. A 32-year-old person with no known exposures or risk factors _____mm induration. Negative Positive Mantoux Tuberculin Skin Test Pre- and Post-Test Answer Key. Correct answer(s) are in bold. 1. The correct amount of PPD antigen to use in . a tuberculin skin test is: a. .05 ml of 5 tuberculin units. b

The general diagnostics of tuberculosis

PPD Skin Test - StatPearls - NCBI Bookshel

Acceptance of the QuantiFERON-TB assay in preference to the tuberculin test as a means of screening for latent tuberculosis infection has grown despite mounting concerns and criticism of the test's performance, including its accuracy and reproducibility (1-18).Central to these concerns are disproportionate numbers of positive results in persons at low risk for infection (3-11) and test. The Tuberculin Skin Test was used before the availability of the blood test, known as QuantiFERON test, to diagnose latent tuberculosis infection. The Tuberculin Skin Test has a drawback, because individuals who have been vaccinated with Bacillus Calmette-Guerin (BCG) vaccine can test positive with the Tuberculin Skin Test These false-positive results accumulated under conditions of standard clinical practice, resulting in unacceptably high false-positive rates. Conclusions that accumulation of false-positive results is mathematically predictable further supports discontinuing the use of the QuantiFERON-TB test in low-risk populations

Often asked: What Happens If You Have A Positive Mantoux Test

Recently, interferon-γ release assays (IGRA) for specific diagnosis of Mycobacterium tuberculosis infection have become available. In recent UK tuberculosis (TB) guidelines, it has been advised to screen for latent M. tuberculosis infection using the tuberculin skin test (TST), followed by IGRA if the TST is positive. Since TST can boost immune responses to tuberculin, the present authors. Furthermore, false-negative and false-positive reactions to the SICCT test can occur due to a variety of reasons relating to both animal- and test-related factors including desensitisation, drugs, physiological status, tuberculin used, incorrect testing technique [Reference De la Rua-Domenech 1] and concurrent infection [Reference Godfray 6] The major test advantage over tuberculin skin test (TST) is that BCG vaccinations and environmental mycobacteria may react with TST but are likely to have false positive QFT-G tests, albeit it can occur up to 9% of the time in foreign born subjects in the U.S. Therefore, the use of QFT-G alone for the detection of latent MT Secondary tests include the gamma interferon blood testor the comparative cervical test ( T). Animals positive to either of the secondary tests are examined for lesions postmortem. All cattle on the premises are quarantined until all testing is complete. audal Fold Tuberculin (FT) Test The FT test is the primary screening test used to identify. Contraindications for tuberculin skin testing • Documented positive skin test . or. active tuberculosis . in the past • Tuberculin reactions that have severely blistered in the past • Clear past history of treatment for TB infection or disease • Extensive burns or eczema at the usual test site. Choose another sit

Nursing Nerds

Pneumonia with positive tuberculin test Pediatric Oncall

The aim of this study was to compare the performance of the T-SPOT. TB TM test, a T-cell-based test, with the tuberculin skin test (TST) in the diagnosis of latent tuberculosis (TB) infection. The study was carried out in 138 immunosuppressed haematology patients who had been nosocomially exposed to a case of smear-positive TB. Overall, 44.2% of the contacts were positive by T-SPOT found to have a positive tuberculin skin test (TST) on routine screening (e.g., employee, travel or educational requirements) and are not valid for interpretation of TST in known TB contacts. STEP 1: Complete recommended medical evaluation. STEP 2: Determine if the TST reaction is considered positive. Refer to table 1 on page 2. The Online TST/IGR A Veterinary Laboratories Agency report 12 reports that between 1st Jan 2005 and 30th Jun 2009, out of 26,363,877 cattle tests, tests using the Weybridge tuberculin found on average that 497 animals tested positive in every 100,000 tests whereas the Lelystad tuberculin only found 391. 12 The ratio given by 497 to 391 closely matches the ratio 0.

Got a tb skin test yesterday - YouTubeTB Screening/Testing Info for New Students - Magers HealthFrontiers | Tuberculin PPD Potency Assays in Naturally

positive tuberculin skin test results that have arisen through ''boosting''. Boosting occurs in people who undergo repeated tuberculin skin tests (such as healthcare workers) and causes false positive skin test results in uninfected people. This phenomenon is High rates of false-positive results on the tuberculin skin test (TST) have been reported among patients treated with methotrexate, regardless of bacillus Calmette-Guerin vaccination status, according to the results of a prospective, single-center cohort study recently published in Seminars in Arthritis and Rheumatism.. The investigators sought to examine whether methotrexate therapy and other. The 2 tests recommended in the UK for detecting TB are tuberculin skin test (TST), otherwise known as the Mantoux test and the blood test known as interferon gamma release assay (IGRA). Skin test: For the TST, a standard dose of purified protein derivative (PPD) tuberculin i A modern replacement to the tuberculin skin test (TST), QFT provides clinicians with an accurate, reliable and efficient tool for aiding the diagnosis of TB infection. QFT is highly specific and sensitive; a positive result is strongly predictive of true infection with M. tuberculosis Mycobacterium tuberculosis is a very unusual pathogen in that infection can be acquired yet remain dormant or latent for many years before reactivation. While the infection is latent, the person has no symptoms or detectable signs of infection, except for a positive tuberculin skin test reaction