24th June 2026

Investigations

All patients with suspected IE should have the following investigations:

• Blood cultures: at least 3 sets, ideally before antibiotics are given, taken from separate sites
• Bloods including WCC, U&Es and CRP/ESR
• ECG: looking for PR prolongation, which may be seen in the presence of an aortic root abscess
• Urine dip: evidence of renal failure
• Chest x-ray
• Trans-thoracic echocardiogram (TTE): first-line imaging investigation for IE

Other investigations to consider are:

• Trans-oesophageal echocardiogram (TOE): may be required if IE suspected but initial TTE is negative
• CT chest: indicated if an aortic root abscess is suspected; may also be required preoperatively in patients requiring surgical management
• Serological testing for culture negative organisms
• Other imaging to look for soft tissue abscess/vertebral osteomyelitis/evidence of septic emboli may also be required

Image Source: Wikimedia Commons (2017). Infective Endocarditis, Licensed under a creative licence. Available for free at: https://commons.wikimedia.org/wiki/Category:Bacterial_endocarditis (Accessed 2 May 2025)