Which of the following is a diagnostic test for Pulmonary Hypertension?

A chest X-ray is often used as one of the initial imaging studies to assess for pulmonary hypertension (PH). It helps in evaluating the heart and lungs, ruling out other conditions, and can show signs like enlargement of the right heart chambers or increased blood flow in the pulmonary arteries. However, while a chest X-ray is useful, it is not definitive for diagnosing pulmonary hypertension alone.

In practice, a comprehensive evaluation is often required, which may include echocardiography, right heart catheterization, and other tests to confirm the diagnosis of pulmonary hypertension. The chest X-ray provides supportive information but is typically not sufficient on its own to diagnose PH without further testing.

The other options listed do not serve as primary diagnostic tests for pulmonary hypertension. An electrocardiogram can indicate changes consistent with right heart strain but is not used to diagnose PH. Allergy testing is unrelated to pulmonary hypertension. Arterial blood gas (ABG) analysis, while helpful in assessing respiratory function, does not provide definitive information regarding the presence of pulmonary hypertension. Thus, among the choices given, a chest X-ray is the most relevant initial diagnostic tool when suspecting pulmonary hypertension.