A patient presents with fever, productive cough, edema, and hypotension. Which diagnostic procedure should be performed first?

• A. ECG
• B. Urinalysis
• C. Chest X-ray
• D. Blood culture

Answer: (D)

When infection with potential sepsis is suspected, the priority is to identify the causative organism before starting antibiotics. A blood culture is the best first diagnostic step because it can reveal bacteremia and guide targeted therapy based on the organism and its antibiotic sensitivities. In a patient with fever, productive cough suggesting pneumonia, edema, and hypotension, there is a high risk of septic shock; obtaining blood cultures promptly helps tailor treatment and improves outcomes.

Chest imaging is important to evaluate the extent of pneumonia, but it does not identify the specific pathogen or its susceptibilities. ECG and urinalysis may be useful in other contexts but do not address the immediate need to pinpoint the infectious agent in this scenario. In sepsis-provoking presentations, blood cultures are drawn before antibiotics to preserve diagnostic yield, while antibiotics are started promptly after cultures are obtained.