The preferred methodology for pre-work clearance in this scenario is the interferon-gamma release assay (IGRA), making option C the correct choice. This conclusion is supported by the guidelines from the Certification Board of Infection Control and Epidemiology (CBIC), which align with recommendations from the Centers for Disease Control and Prevention (CDC) for tuberculosis (TB) screening in healthcare workers. The employee’s history of receiving the Bacillus Calmette-Guérin (BCG) vaccination, a vaccine commonly used in some countries to prevent severe forms of TB, is significant because it can cause false-positive results in the traditional Tuberculin skin test (TST) due to cross-reactivity with BCG antigens (CBIC Practice Analysis, 2022, Domain I: Identification of Infectious Disease Processes, Competency 1.3 - Apply principles of epidemiology).
The IGRA, such as the QuantiFERON-TB Gold test, measures the release of interferon-gamma from T-cells in response to specific TB antigens (e.g., ESAT-6 and CFP-10) that are not present in BCG or most non-tuberculous mycobacteria. This makes it a more specific and reliable test for detecting latent TB infection (LTBI) in individuals with a history of BCG vaccination, avoiding the false positives associated with the TST. The CDC recommends IGRA over TST for BCG-vaccinated individuals when screening for TB prior to healthcare employment (CDC Guidelines for Preventing Transmission of Mycobacterium tuberculosis, 2005, updated 2019).
Option A (referral to tuberculosis clinic) is a general action but not a specific methodology for clearance; it may follow testing if results indicate further evaluation is needed. Option B (initial chest radiograph) is used to detect active TB disease rather than latent infection and is not a primary screening method for pre-work clearance, though it may be indicated if IGRA results are positive. Option D (two-step purified protein derivative-based Tuberculin skin test) is less preferred because the BCG vaccination can lead to persistent cross-reactivity, reducing its specificity and reliability in this context. The two-step TST is typically used to establish a baseline in unvaccinated individuals with potential prior exposure, but it is not ideal for BCG-vaccinated individuals.
The IP’s role includes ensuring accurate TB screening to protect both the employee and patients, aligning with CBIC’s focus on preventing transmission of infectious diseases in healthcare settings (CBIC Practice Analysis, 2022, Domain III: Infection Prevention and Control, Competency 3.2 - Implement measures to prevent transmission of infectious agents).
[References: CBIC Practice Analysis, 2022, Domain I: Identification of Infectious Disease Processes, Competency 1.3 - Apply principles of epidemiology; Domain III: Infection Prevention and Control, Competency 3.2 - Implement measures to prevent transmission of infectious agents. CDC Guidelines for Preventing Transmission of Mycobacterium tuberculosis, 2005, updated 2019., , , ]
