What is this test?
Creatinine is a waste product influenced by muscle metabolism and removed mainly by the kidneys. It is commonly used to calculate estimated kidney filtration.
Why might it be ordered?
- To assess kidney function or monitor a kidney condition.
- Before or during medicines, contrast procedures or illnesses that can affect the kidneys.
What sample is needed?
A blood sample is required. The laboratory chooses the correct tube and handles the sample for this test.
How should you prepare?
Ask the laboratory whether you need to fast or attend at a particular time. Do not stop or change medicines or supplements unless your clinician tells you to.
How should you understand the result?
A higher value can reflect reduced filtration but also muscle mass, dehydration, diet and some medicines. eGFR usually adds more context than creatinine alone.
Sources and editorial status
This patient-facing text is an editorial draft. It should be approved by a laboratory physician before official publication.