The Gold-Standard Test for a Pulmonary Embolism

Respiratory · Question from the ATI RN Medical-Surgical 2023 Proctored Exam study set

Correct answer: C. CT Pulmonary Angiography

Why this is the answer

CT Pulmonary Angiography (CTPA) directly visualizes clots in the pulmonary vasculature, making it the definitive confirmatory test. A chest X-ray (A) is often normal or only shows nonspecific findings in a PE — it can't confirm the diagnosis. An EKG (B) may show sinus tachycardia or nonspecific changes but isn't diagnostic for PE. D-dimer (D) is highly sensitive but not specific — many conditions besides PE elevate it, so it's used mainly to help rule PE out when negative, not to confirm it when positive.

The bigger concept

A useful distinction across many exam questions: sensitive tests (like D-dimer) are good for ruling a condition out when negative, while specific tests (like CTPA) are good for ruling a condition in when positive. Knowing which category a test falls into tells you what a given result can and can't prove.

Related Respiratory practice questions

• Interpreting an ABG in a COPD Exacerbation
• What a V/Q Scan Actually Measures
• Chest Tube 'Tidaling' in the Water-Seal Chamber
• Subcutaneous Emphysema Around a Chest Tube Site
• Assessment Findings in a Tension Pneumothorax

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