Preparing for Your Lab Work
Following these instructions carefully ensures the most accurate results — and the most effective treatment plan for your child
Most Important:
Stop all antihistamines at least 14 days before lab work. This includes Benadryl, Zyrtec, Claritin, Allegra, and any allergy or sleep medications containing antihistamines. Also stop zinc and Vitamin D supplements unless Dr. Lewis instructs otherwise. These significantly affect multiple lab values.
Lab Preparation Timeline
Follow each phase carefully for the most accurate results
2 Weeks Before
- Stop ALL antihistamines completely (Benadryl, Zyrtec, Claritin, Allegra, etc.)Critical
- Stop Vitamin D supplements (unless told otherwise by Dr. Lewis)Critical
- Stop zinc supplementsCritical
- Continue all other prescribed medications unless instructed otherwise
Antihistamines significantly affect lab results and must be stopped at least 14 days before testing.
Day Before
- Drink at least 8 glasses of water throughout the day
- Avoid vigorous exercise — light walking is fine
- Eat normally — no fasting required unless specifically instructed
- Get a full night of sleep
Good hydration the day before makes blood draws significantly easier, especially for children.
Day of Labs
- Continue hydrating — drink water before the appointment
- Eat a normal breakfast (unless fasting has been specifically requested)
- Bring a complete list of all current medications and supplements
- Dress your child in short sleeves or a loose top for easy access
- Bring a comfort item for younger children (stuffed animal, blanket)
We use a calm, child-friendly approach to blood draws. Please let us know if your child has had difficult experiences with needles.
Important Window
- All labs must be completed within 2 weeks of your visit dateCritical
- Results received after this window may delay your appointmentCritical
- Contact us immediately if you have any scheduling conflicts
Lab results are essential for Dr. Lewis to prepare a comprehensive treatment plan for your visit. Timing matters.
Lab Preparation FAQs
Have Questions?
Our staff is happy to clarify any instructions before your appointment.
Ready to Begin?
Lab preparation is an important step toward accurate diagnosis and effective treatment. We're here to guide you through every part of the process.