Which initial investigations should be performed in a patient presenting with acute chest pain in primary care?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 16 August 2025Updated: 16 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

Perform a resting 12-lead ECG as soon as possible to identify any abnormalities suggestive of acute coronary syndrome (ACS) or other cardiac causes .

Take a blood sample for high-sensitivity troponin I or T measurement to help diagnose myocardial infarction, ideally on arrival in hospital or as part of initial assessment .

Carry out a physical examination to assess haemodynamic status, signs of complications such as pulmonary oedema, and signs of non-coronary causes like aortic dissection .

Monitor oxygen saturation using pulse oximetry, and consider supplemental oxygen only if saturation is below 94% or if the patient has chronic respiratory conditions at risk of hypercapnic respiratory failure .

Assess the characteristics of the pain, associated symptoms, and risk factors through detailed history-taking, which guides further investigations .

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