A 25-year-old man comes to the employee health center for a physical examination prior to starting work as a patient care technician in a community hospital. The patient's family immigrated to the United States from Eastern Europe when he was a toddler. He received a medical evaluation prior to immigrating, but the records are not available. The patient has had no fevers, chills, night sweats, weight loss, cough, or fatigue. He has no chronic medical problems and takes no medications. He consumes alcohol occasionally but does not use tobacco or illicit drugs. The patient went on a 2-month backpacking trip through Central and South America a year ago. His immunization records are up to date. He has a small scar in the right deltoid area and notes that he received a bacillus Calmette-Guérin vaccination as an infant. The patient has no other abnormalities on physical examination. Item 1 of 2
Regarding pre-employment evaluation for tuberculosis, which of the following is the most appropriate next step in management of this patient?

Question

Quizplus · Accepted Answer

Explanation: Health care personnel (HCP) are at risk for workplace exposure to Mycobacterium tuberculosis. Prior to beginning employment, these individuals should be screened for tuberculosis (TB) to document baseline TB status. Screening can be done with either a tuberculin skin test (TST), which requires intradermal tuberculin injection, or interferon-gamma release assay (IGRA), which requires a blood sample. Although roughly comparable in accuracy, IGRA has 3 main advantages over TST: No false positives in patients with previous bacillus Calmette-Guérin (BCG) vaccine: BCG vaccine administration can cause an initial TST reaction of up to ~20 mm; serial vaccination, practiced in some countries, can boost this response. The TST reaction generally wanes with time (eg, <10 mm 10 years after BCG vaccine administration). No need for a return visit to measure induration size: The TST reaction should be read 48-72 hours after intradermal tuberculin injection. No need for 2-step confirmation: Patients who were exposed to mycobacterial antigens remotely can have a negative result to an initial TST (due to waned immunity) but a positive result to a second, "booster" TST weeks later (due to anamnestic response following the initial TST); for HCP (and close contacts of patients with active TB), a second TST is often recommended 1-4 weeks later to confirm a negative initial test. IGRA is not subject to the "booster" phenomenon. This patient who previously received a BCG vaccine should be screened with an IGRA, not a TST (Choice D). (Choice A) Although the BCG vaccine is associated with reduced risk of active tuberculosis, protection wanes 10-15 years after vaccination. In addition, all patients who work in the health care setting require pre-employment screening for TB regardless of immunization status. (Choice B) Patients who have a history of latent TB are likely to have a positive TST and IGRA for life. As a result, these patients are typically screened for TB with a chest radiograph. (Choice E) Patients with abnormal screening tests who have symptoms (eg, chronic cough, fever, night sweats) or radiographic findings (eg, cavitation, infiltrate) concerning for active TB require microbial confirmation with sputum acid-fast bacillus samples and culture. This patient is asymptomatic and should be screened with an IGRA. Educational objective: Individuals who work in the health care setting should receive pre-employment tuberculosis (TB) screening to establish baseline TB status. Two main screening tools are used: tuberculin skin test and interferon-gamma release assay (IGRA). An IGRA should be used to screen for TB in most patients with previous bacillus Calmette-Guérin vaccine as these patients may have a false-positive tuberculin skin test.

A 25-Year-Old Man Comes to the Employee Health Center for a Physical