How do I prepare for a pathology test? Do I need to fast?

Yes, fast for 8-12 hours before your test. Water is allowed and encouraged.

Before Your Test — Fasting Requirements

Duration: 8-12 hours (overnight fasting works well)
Water: Yes, please stay hydrated
Black coffee/tea: No — these can affect results
Medications: Continue as normal unless advised otherwise
Timing tip: Book morning appointments to make fasting easier

What to Bring

Photo ID
Pathology referral (digital or printed)
Medicare card (if applicable)
List of current medications

Day Before Your Test

Eat normally until your fasting period begins
Avoid alcohol for 24 hours
Stay well-hydrated
Get a good night’s sleep

What happens if I have fasted for over 12 hours?

Most tests remain accurate — The 8-12 hour window is optimal, but slightly longer won’t invalidate most results. Your pathology provider can advise if your specific tests require stricter timing.

Some markers may shift slightly — Blood glucose may drop lower than baseline, and cortisol levels might elevate slightly.

What to Do

Up to 16 hours: Proceed with your test — results should still be reliable
Over 16 hours:
- Inform the pathology nurse about your fasting duration
- They’ll note it for the interpreting doctor
- Still better to test than reschedule in most cases

When to Be Concerned

Feeling faint or dizzy: Have a small glass of water and sit down
Diabetic or hypoglycaemic: Don’t extend fasting — stick to 8-12 hours
Over 24 hours: Consider rescheduling as this may affect accuracy

Pro Tips

Set an alarm to remind yourself when to start fasting
Book early morning appointments (7–9 AM) to minimise fasting discomfort
Stay hydrated — water doesn’t break your fast and prevents dehydration