Tuberculin skin test

Infectious patients present a difficult challenge when trying to protect health care workers. These patients must be isolated from the health care workers as well as from the other patients in the hospital. Special isolation rooms are used for this purpose. These rooms are generally used for isolation of infectious tuberculosis (TB) patients, but could be used for patients with other airborne-transmitted diseases. In the United States, there were 22 812 new cases of tuberculosis in 1993, equal to 8.7 per 100 000 population. This represents a 2.8% increase since 1985, following a 6-7% annual decline from 1981-1984.Several studies have documented higher than expected tuberculin skin test (TST) conversion rates in hospital personnel.The National Institute for Occupational Safety and Health " reports that multiple-drug-resistant (MDR) strains of TB have been reported in 40 states and have caused outbreaks in at least 21 hospitals, with 18-35% of exposed workers having documented TST conversions. 

Those whose tuberculin skin test has become positive in the last 2 years... 

Because of the risks of adverse reaction to the vaccine by persons who had already been exposed to the disease a sensitivity test must be carried out prior to immunization with BCG. A Mantoux skin test assesses an individual s sensitivity to a purified protein derivative (PPD) prepared fi om heat-treated antigens (tuberculin) extracted fiom M tuberculosis. A positive test imphes past infection or past, successful immunization Those with strongly positive tests may have active disease and should be referred to a chest clinic. Many people with active TB, especially disseminated TB, however, sero-convert fiom skin test positive to skin test negative. Results of the skin test must therefore be interpreted with care. 

Prior to initiating infliximab, obtain a tuberculin skin test to rule out latent tuberculosis. Assure that patients do not have a clinically significant systemic infection or New York Heart Association Class III or IV heart failure. 

The patient was admitted and placed on respiratory isolation. Three separate sputum Gram stain specimens were reported to contain 3+ AFB. A PPD tuberculin skin test was placed. Sputum samples were sent for AFB, fungi, and bacterial cultures and sensitivities. After 48 hours, the PPD skin test was read as a 12-mm area of induration. 

Purified protein derivative (PPD) Material used in the tuberculin skin test, the most common test for exposure to Mycobacterium tuberculosis. 

Etanercept 50 mg SC once weekly Tuberculin skin test None... 

The most widely used screening method for tuberculous infection is the tuberculin skin test, which uses purified protein derivative (PPD). Populations most likely to benefit from skin testing are listed in Table 49-2. 

Evaluate patients for latent tuberculosis infection with a tuberculin skin test. Initiate treatment of latent tuberculosis infection prior to therapy with infliximab. 

Tuberculin skin testing is an important part of the care of all HIV-1-infected patients or persons at risk for HIV-1 infection. Tuberculin skin testing should be done using the Mantoux method. A tuberculin reaction of >5 mm of induration is classified as positive in persons known to have or suspected of having HIV-1 infection. Unfortunately, as the CD4 lymphocyte count declines with progression of HIV-1 disease, many patients no longer react to delayed-type hypersensitivity testing. More than 60% of persons with CD4 lymphocyte counts of <200 cells/pl may have skin test reactions of <5 mm. Thus, it is impossible to detect the presence of tuberculous infection in many HIV-l-infected individuals. 

HIV-1 seropositive persons should be treated for LTBI if they have a tuberculin skin test >5 mm and have not previously received treatment for LTBI. In certain cases, treatment of LTBI in persons who are not tuberculin positive may also be considered. Such therapy may be beneficial for ... 

Tuberculosis Persons with positive tuberculin skin tests and one or more of the following (a) HIV infection, (b) close contacts with newly diagnosed disease, (c) recent skin test conversion, (d) medical conditions that increase the risk of developing tuberculosis, (e) age < 35 Isoniazid, rifampin, or pyrazinamide Excellent... 

A thorough history and examination is important to determine the cause of phlyctenulosis. Inspect the lid margins for signs of staphylococcal blepharitis and question the patient regarding recent infections or tuberculosis exposure. If there is reason to suspect tuberculosis or if no other cause can be found, a tuberculin skin test may be indicated. If diarrhea or gastrointestinal distress is present, consider a stool examination for nematodes. 

Patients with phlyctenulosis should be reevaluated in 3 to 4 days. Significant improvement in signs and symptoms should occur within 48 hours. If the tuberculin skin test is positive, chest x-rays and a medical consultation are indicated. 

Burgoyne CF, Verstraeten TC, Friberg TR. Tuberculin skin-test-induced uveitis in the absence of tuberculosis. Graefes Arch Clin Exp Ophthalmol 1991 229(3) 232-6. 

Organomercurials have been a common cause of allergic contact dermatitis or rash (22) and even exfoliative dermatitis has been described (23). Some reagents for intra-cutaneous testing (tuberculin, etc.) may contain thiomersal, which can cause sensitization and thus elicit false-positive delayed-type skin reactions. Mercury compounds inhibit most lymphocyte functions (SEDA-21, 240). An early indicator of an immunological response to mercury exposure, for example in occupational medicine, appears to be a change in the lymphocyte count with a differential increase in T helper cells and a rise in the T helper/T suppressor ratio (24). 

Over 1 to 3 months, activated lymphocytes reach an adequate number, and tissue hypersensitivity results. This is shown by a positive tuberculin skin test. Any remaining mycobacteria are believed to reside primarily within granulomas or within macrophages that have avoided detection and lysis, although some residual bacilli have been found in various types of cells. "... 

Bacille Calmette-Guerin Vaccine (BCG). The BCG vaccine is an attenuated, hybridized strain of M. bovis. It was developed in 1921 and is used as a prophylactic vaccine against TB. Administration of BCG vaccine is compulsory in many developing countries and is officially recommended in many others. Vaccination with BCG produces a subclinical infection resulting in sensitization of T-lymphocytes and cross-immunity to M. tuberculosis, as well as cutaneous hypersensitivity and, in many cases, a positive tuberculin skin test. 

American Thoracic Society/Centers for Disease Control and Prevention. Targeted tuberculin skin testing and treatment of latent mberculosis infection. Am J Respir Crit Care Med 2000 161 8221-247. 

Adverse effects of the rubella virus vaccine tend to increase with the age of the recipient. Symptoms are similar to wild-virus infection and include lymphadenopathy, rash, urticaria, fever, malaise, sore throat, headache, myalgias, and paresthesias of the extremities. These occur 7 to 12 days after vaccination and last 1 to 5 days. Joint symptoms occur more often in susceptible postpubertal females. Arthralgia occurs in 25% of such vaccinees, and 10% will have arthritislike symptoms. These symptoms usually begin 1 to 3 weeks after vaccination and persist for 1 day to 3 weeks. A very small excess risk of chronic arthropathy exists. The vaccine may cause suppression of tuberculin skin tests for up to 6 weeks after vaccination. While the vaccine virus may be excreted in nose and throat secretions, it is not contagious. 

Huebner RE, Schein MF, Bass JB. The tuberculin skin test. CUn Infect Dis 1993 17(6) 968-975. 

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