Baseline bloods including FBC, U&Es and LFT should be taken. INR should be taken if the patient is on warfarin.
Infection, renal or liver failure, anaemia or electrolyte abnormalities can be identified which may precipitate or exacerbate CPO.
Hyponatraemia and raised urea and creatinine are associated with poor outcome.
Troponin should be measured and may support an ACS diagnosis (which is associated with an adverse outcome) but small rises in Troponin can occur in CPO with out ACS.