Blood tests

Full blood count (the white cell count may be low in overwhelming bacterial sepsis; a low platelet count may reflect disseminated intravascular coagulation)

Clotting screen if purpura or jaundice, prolonged oozing from puncture sites, bleeding from surgical wounds or low platelet count

C-reactive protein

Sodium, potassium, urea and creatinine

Blood glucose (hypoglycaemia can complicate sepsis, especially in patients with liver disease)

Liver function tests

Amylase

Arterial gases, pH and lactate

Microbiological tests (Table35.3)

Imaging

Chest X-ray

Other imaging as directed by the clinical picture

Other tests

ECG if aged >50, history of cardiac disease or suspicion of arrythmia