Initial investigations in primary care for suspected acute bowel ischaemia should focus on urgent clinical assessment and basic blood tests. These include a full blood count, urea and electrolytes, and C-reactive protein to assess for signs of inflammation, infection, or organ dysfunction. If these inflammatory markers are raised, urgent referral for hospital assessment and imaging (such as contrast-enhanced CT) is required to confirm diagnosis and guide management. In primary care, no specific imaging is recommended due to the need for rapid specialist assessment. Clinical signs of sepsis or peritonitis warrant immediate hospital referral rather than delay for investigations in primary care.
Therefore, the initial primary care investigations are blood tests (full blood count, urea and electrolytes, C-reactive protein) combined with clinical assessment to identify severity and need for urgent referral.