Before having your blood sample taken, you should fast for 8–12 hours. Alcohol, sugar and coffee may affect the reliability of the results. As smoking may also influence the results, patients are advised not to smoke between waking up and having their blood taken. Only small amounts of water (one or two glasses) are permitted.
Diet
In the days leading up to the blood test, continue to follow your usual diet. The purpose of the tests is to assess the levels and characteristics of metabolites normally present in the body. Excessive food intake or a restrictive diet may affect both the laboratory results and their clinical interpretation.
Medications
Unless otherwise instructed by a doctor, patients should have their blood sample taken before taking any medication.
Urine sample collection (standard urine test)
- Use a sterile disposable container with a secure lid and a label suitable for recording the required patient information. These containers are available from the laboratory or any pharmacy.
- Wash your hands and genital area before urinating.
- Collect a small amount of urine from the first urination of the morning, after discarding the initial stream.
- Deliver the sample as soon as possible.
