Which of the following is NOT a diagnostic test for Bronchiectasis?

In the context of diagnosing bronchiectasis, the correct choice is the electrocardiogram (ECG), as it is not a diagnostic test for this condition. Bronchiectasis is a chronic lung condition characterized by the abnormal and permanent dilation of the bronchi, which is primarily associated with infections, cystic fibrosis, or other diseases that can lead to inflammation and damage of the airways.

Chest X-rays and CT scans are directly related to assessing bronchiectasis; they can reveal structural changes in the lungs. A CT scan, in particular, is considered the gold standard for diagnosing bronchiectasis as it provides detailed images of the bronchial tubes and is effective in showing the classic signs of the disease, such as bronchial dilation and wall thickening.

Arterial blood gas (ABG) analysis, while not specific for diagnosing bronchiectasis, can be useful in assessing the patient's oxygenation and carbon dioxide removal capabilities, providing insight into the respiratory function of a patient with advanced disease.

The ECG, however, is primarily a test used to evaluate the electrical activity of the heart. While it can provide valuable information about cardiovascular conditions, it does not provide any relevant data regarding lung structure or function directly associated with bronchiectasis.