What should you know about an ECG and blood test?

An ECG can show heart rate, rhythm and conduction at the moment of recording. Blood tests can look for changes such as anaemia, inflammation, infection, electrolyte disturbance or altered organ function, depending on the panels ordered. Together, they may help explain symptoms such as palpitations, breathlessness, dizziness or unusual tiredness. Neither test gives a complete diagnosis on its own. A clinician considers the result pattern, symptom history, examination and any medicines you take.

The ECG usually involves lying still while electrodes are placed on the skin. The blood test involves a sample from a vein. Ask whether fasting is required for any additional blood tests, and follow the specific instructions you receive. Tell the team about medicines, supplements, allergies, needle concerns and recent illness. Drink water unless you have been told to restrict fluids. Do not stop prescribed medicines unless the clinician who manages them instructs you to do so.

Seek emergency help for chest pressure or pain, severe breathlessness, fainting, new confusion or a fast or irregular heartbeat with severe dizziness. Do not wait for test results if symptoms are sudden or worsening. Contact the ordering clinician if results are difficult to understand or symptoms continue despite reassuring findings.

Ask what each test is intended to investigate, whether you need preparation, and when results will be reviewed together. Ask which result needs follow-up, whether medicines may affect interpretation, and what symptoms should lead you to urgent care.