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Management of Patients with a Positive Tuberculin Skin Test (TST)
Management of Patients with a Positive Tuberculin Skin Test (TST) - Clinical Hub, References, Infection Control, Infection Control, Tuberculosis Control
- A TST should never be used to rule out the presence of active tuberculosis (TB) infection in a patient with suggestive signs and symptoms
- Performing a TST implies that treatment will be provided to patients with a positive test result (According to the American Thoracic Society and Infectious Disease Society of America “A decision to test is a decision to treat”). Providers should factor in concerns about treatment-related toxicity and the likelihood of offering treatment for latent tuberculosis infection (LTBI) prior to performing a TST as indiscriminate testing can lead to false-positive test results and unnecessary patient anxiety. Please go to http://www.tstin3d.com/ and/or http://www.cdc.gov/mmwr/preview/mmwrhtml/rr4906a1.htm for more information on which patients to screen for LTBI using the TST.
- A negative TST does not rule out the presence of LTBI in patients with recent exposure to TB. High-risk individuals (children under the age of 5, highly immunosuppressed patients) exposed to another patient with active TB should be started on therapy for LTBI even when the TST is negative. A second TST should be repeated 8-10 weeks after the exposure and therapy for LTBI may be discontinued if this second TST remains negative.
The following steps should be followed when confronted with a patient with skin induration ³ 5mm following placement of a TST
- Determine the patient’s risk category (high, moderate, low) in order to establish the induration size that distinguishes a positive from a negative test result (see table).
- Perform a clinical assessment to determine if the patient has unexplained fever, cough or weight loss.
- If no symptoms of active pulmonary TB infection, a chest radiograph should be obtained based on their risk category.
- Patients with a positive PPD, no active symptoms and negative chest x-ray do not require Airborne Precautions
- If the patient presents with any of these symptoms and has a positive TST (based on their risk category) the patient may have active pulmonary TB infection
- Place the patient in Airborne Precautions immediately
- The patient is required to wear a mask when ambulating outside of an Airborne Infection Isolation (AII) room (e.g., sent to Radiology)Contact Infection Control (UWMF: (608) 826-6730/UWHC: pager 2570) for questions, reporting of communicable diseases, or exposure follow-up
- Patients with a positive TST (based on their risk category) who have no symptoms and a negative chest radiograph should be offered treatment for LTBI as detailed in the ATS/IDSA Guidelines (http://www.cdc.gov/mmwr/preview/mmwrhtml/rr4906a1.htm).
- Patients with a positive TST (based on their risk category) and either signs/symptoms of active pulmonary TB infection oran abnormal chest radiograph should have sputum obtained for AFB smears.
- (608) 826-6730/UWHC: pager 2570) should be contacted whenever a patient is found to have a positive AFB smear. Three AFB smears are required to be negative before a patient is considered non-infectious and allowed to have contact with healthcare workers and other patients.
- For Inpatients refer to the Control of Tuberculosis Policy 4.1.1 for criteria on how to remove patients from airborne precautions.