What confirmatory value do the three IPF tests have for interstitial lung disease

The three IPF tests refer to IPF radionuclide imaging, IPF pulmonary function, and IPF lung biopsy. Each has its own advantages, and when the three are used in combination, like a powerful alliance, they can confirm the cause of idiopathic pulmonary fibrosis and various other interstitial lung diseases from multiple angles, levels, and dimensions, and provide an accurate basis. For example, with IPF radionuclide imaging, inhaling 99mTc-DTPA aerosol can increase alveolar-capillary membrane permeability, allow measurement of LEP epithelial permeability, and show shortened T1/2, which helps in the early detection and diagnosis of interstitial lung disease.

IPF pulmonary function testing can obtain indices of the typical pulmonary function changes in interstitial lung disease, such as restrictive ventilatory impairment, reduced lung volumes, decreased lung compliance, and reduced diffusion capacity. If PaO2 decreases and PA-aO2 widens, it indicates that the interstitial lung disease is already severe and close to interstitial pulmonary fibrosis. In particular, post-exercise testing showing reduced diffusion capacity, hypoxemia, and imaging changes is helpful for early confirmation.

Dynamic observation of pulmonary function tests is very informative for predicting the course of IPF, and can also assess the efficacy of treatment for interstitial lung disease and idiopathic pulmonary fibrosis. However, if no specific IPF pulmonary function abnormalities appear, then it has no diagnostic value. If the total cell count in the recovered bronchoalveolar lavage fluid increases and the proportion of neutrophils rises, this is helpful for confirming IPF, although at present it is still mainly used for research.

Lung biopsy can identify early- and mid-stage IPF histological changes, and many causes of interstitial lung disease include those with clearly identifiable causes. Therefore, lung biopsy is very meaningful for confirming interstitial lung disease and evaluating disease activity. The preferred approach is TBLB via fiberoptic bronchoscopy, but the specimens are small and diagnosis is sometimes still difficult; when necessary, open lung biopsy should be performed.