Performance Gold

Fasting

• Alcohol before your test

  24-48 hours

  Avoid alcohol for at least 24 hours before your test. Allow 48 hours without alcohol where lipid markers are being assessed.

Sample timing

• Sample timingCortisol is ideally taken between 08:00 and 09:00. Testosterone is best measured in the morning, before 11:00.

Activity

• Exercise before your test

  24 hours

  Avoid strenuous or unusually intense exercise for at least 24 hours before your test. Normal light activity such as walking is fine. Hard exercise can temporarily affect CRP. Hard exercise can temporarily affect full blood count results. Hard exercise can temporarily raise creatine kinase.
• Biotin supplements

  48 hours

  Stop biotin (vitamin B7) supplements 48 hours before your test, including multivitamins and hair, skin and nail supplements. If biotin was prescribed, speak to your prescriber before stopping. Biotin can interfere with thyroid tests.

Medication and supplements

• Iron and supplement preparation

  24 hours

  Avoid iron and other vitamin or mineral supplements for 24 hours before your draw. Do not stop prescribed iron without clinical advice. Recent supplement intake can affect serum iron.
• Vitamin D supplement note

  24 hours

  Avoid vitamin D supplements for 24 hours before your test and note the dose and timing of your most recent one. Do not stop prescribed vitamin D without clinical advice.
• Thyroid medication timing

  Day of test

  Thyroid samples are best taken between 06:00 and 10:00, before your daily thyroid medication. Do not change your prescribed regimen without clinical advice.