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Discovered in 1882, tuberculosis (TB) is a potentially lethal infectious disease with severe complications. While its eradication in developed countries is substantial, TB is still contributing to morbidity and mortality in many parts of the world. Caused by the bacterium Mycobacterium tuberculosis, this disease primarily affects the lungs, resulting in decreased breathing capacity. Most individuals who contract an infection with TB will eliminate or contain the infection, resulting in latency. Transmission occurs through respiratory droplets from individuals with active disease. Reactivation of latent disease causes the resurgence of symptoms and the spread of the disease. [1] There are currently 2 testing methods for identifying latent tuberculosis infection: the tuberculin skin test (TST) and the interferon-gamma release assay (IGRA). IGRA tests diagnose tuberculosis infection by either calculating the concentration of interferon-γ generated ex vivo by the patient's immune cells or by counting the total number of interferon-γ-secreting lymphocytes. The TST is performed by injecting a small amount of tuberculin purified protein derivative fluid subcutaneously into the forearm. Induration is measured 48 to 72 hours post-injection. The size of induration and the patient's risk factors together determine the test results.[2] Conversely, the diagnosis of active TB is clinical, with confirmatory testing through sputum culture analysis.

Bacilli tubers invade the upper respiratory tract and travel in small (5 to 10 microns) droplets to the alveolar spaces. When the host's immune system does not eradicate the bacteria, the bacilli propagate within macrophages and ultimately destroy the cells. Infected macrophages generate inflammatory cytokines and recruit additional phagocytes, forming a nodular, caseating granuloma known as a tubercle. The granuloma prevents the infection from spreading to other areas of the lungs. If bacterial proliferation is not regulated, the tuber may expand, seeding infection to other areas, including the lymphatic system. The resulting inflammation leads to mediastinal lymphadenitis, a clinical manifestation of TB. The cyst, caused by the growth of the tubercle into lung tissue and resulting lymphadenopathy, is known as the Ghon complex and is a classic radiographic finding in primary tuberculosis infection.[10][11] Interferon-γ is the primary cytokine released in response to infection by M tuberculosis bacteria. Macrophages are the first immune cells to respond to infection. Following phagocytosis, macrophages secrete cytokines to attract T helper cells, the primary mediators of interferon-γ. Interferon-γ further amplifies the activation of macrophages. This activation-reactivation process between macrophages and T helper cells occurs repeatedly as a positive feedback loop until the infection is eradicated or dormant. IGRAs quantify the immune reaction of T helper cells to detect latent TB. Fresh blood samples are mixed with antigens and controls to determine if infection is present.[12][13]

In the context of IGRA testing, interprofessional collaboration is essential to ensure accurate diagnostics, patient safety, and optimal care outcomes. Nurses and phlebotomists are responsible for collecting specimens properly and transporting them in a timely manner to maintain sample integrity. Meanwhile, laboratory technologists ensure the rigorous implementation of internal and external quality control protocols. Clinicians must communicate clearly with the laboratory, providing relevant clinical context to support accurate interpretation of results and timely clinical decision-making. Pharmacists contribute by assessing and managing treatments when TB infection is confirmed. All team members must uphold ethical considerations—such as informed consent, confidentiality, and equitable access to testing. Effective interprofessional communication, regular case reviews, and shared decision-making promote a patient-centered approach, thereby enhancing diagnostic accuracy and clinical outcomes. Coordinated care pathways, continuous quality improvement, and team training strengthen healthcare team performance and reduce the risk of diagnostic errors or delays in TB management.