Final answer:
The initial diagnostic test that should be ordered when suspecting pulmonary hypertension is an echocardiogram.
Step-by-step explanation:
When suspecting pulmonary hypertension, the initial diagnostic test that should be ordered is an echocardiogram. This test uses sound waves to create images of the heart and can provide information about the size of the heart, the blood flow, and any abnormalities in the heart's structure and function. Echocardiography is a non-invasive and cost-effective test that can help confirm the diagnosis of pulmonary hypertension.