Blood test

A blood test examines a sample of blood to help assess health, investigate symptoms or monitor a condition or treatment. Different tests answer different questions, so there is no single blood test that checks everything. A clinician chooses tests according to the clinical question and interprets results alongside your history.

Do I need to fast?

Only when the ordering clinician or collection service instructs you to. Preparation differs between tests. Ask whether you should eat, drink or take usual medicines, and do not stop prescribed treatment without specific advice. Tell the collection staff if you did not follow preparation instructions.

Bring the request form or electronic details, identification and relevant billing information. Mention previous fainting, difficult blood collection or a fear of needles. Staff can explain the process and discuss practical support.

For the Australian guidance behind this explanation, see Healthdirect Australia: Guide to blood testing.

What does an abnormal result mean?

A result outside the laboratory reference range does not automatically establish a disease, and a result inside the range does not answer every clinical question. Age, pregnancy, timing, recent illness and other factors can affect interpretation. Trends may be more useful than one isolated number.

Ask the ordering clinician what the test is intended to investigate and how the result will change care. Avoid ordering broad panels simply because they are available. More testing can create uncertain findings as well as useful information.

Who follows up the result?

Confirm how and when you will hear from the service and who is responsible for reviewing it. Do not assume no news means normal. If symptoms worsen while waiting, seek appropriate care rather than waiting only for the result.

See Doccio's tests information for its current process. A doctor decides whether testing is appropriate, and collection-centre fees or eligibility may vary. An online consultation can support interpretation, but further examination or repeat testing may be needed to understand an unexpected finding.

Where to go next

Read tests to understand the relevant service. A doctor decides whether a consultation, examination, referral or another pathway is appropriate for your situation.