Can I order this test on its own?

Most labs can be ordered on their own with the “Lab Only” option, which includes a general results review. If you’d like your results personally reviewed — with a written Root Cause Report and personalized 12-week protocol — explore the 12-Week Program. Either way, add Tiffeny Parker as your practitioner when you register your kit so I can see your results.

Is this a medical diagnosis?

No. Functional lab testing is educational and is used to guide nutrition, lifestyle, and supplement strategy. It does not diagnose, treat, or cure any disease. Always work with your licensed healthcare provider for medical concerns.

How long do results take?

Most kits are collected at home in a single day and returned by prepaid mail. Results typically take about 2–4 weeks, depending on the panel.

Targeted Single-Marker Tests

Optimal Vitamin D Test

Also known as: 25-hydroxy vitamin D

The hormone-like vitamin behind immunity, mood, bones, and mineral balance.

Dried blood spot (finger prick)At-home collection kit

How to get this lab ↓

Vitamin D acts like a hormone for immunity, mood, bone, insulin sensitivity, and calcium/magnesium balance. We aim for optimal, not just "not deficient."

What it measures

What's measured

25-hydroxy vitamin DThe storage form of vitamin D — the best measure of your overall status.

Who this is for

Useful for nearly everyone, especially if you spend most of your time indoors or live where winters are long.

Getting sick often
Low mood, especially in winter
Bone or muscle aches
Fatigue
Little sun exposure

Two ways to get the Optimal Vitamin D Test

Lab Only

Available to program members — ordered and reviewed by Tiffeny.

Personalized with Tiffeny

Recommended

Want your results personally reviewed?

One-on-one interpretation of your results
Written Root Cause Report
Personalized 12-week protocol

✦ Members receive exclusive pricing on multi-lab orders. See member perks →

Labs are processed by a CLIA-certified laboratory partner. To protect your privacy, I can only see your results if you add Tiffeny Parker as your practitioner.

Questions about your lab? Send a message →

What results can reveal

Low or suboptimal vitamin D
Whether your current dose is enough

How we interpret it

We read every panel through a functional lens — optimal reference ranges, ratios, and cross-panel patterns. Results become part of your written Root Cause Report and your personalized 12-week protocol.

Vitamin D works hand in hand with calcium and magnesium, so we dose it carefully against your HTMA to keep those minerals in balance.

Often paired with

Minerals & Metals Test

Cellular mineral status and heavy metal burden — the foundation of the Method.

Stress, Mood & Metabolism Test

Sex hormones, cortisol, full thyroid, blood sugar, and vitamin D — the complete hormone picture.

Common questions

Not sure which panels you need?

Start with the Root-Cause Fit Assessment. Takes about 3–5 minutes. If it looks like we're a good fit, you'll be invited to schedule a 45-minute consultation to discuss your health history, goals, and whether this program is the right next step for you.

Educational information only. Functional lab testing is not intended to diagnose, treat, cure, or prevent any disease. Results are reviewed in the context of your full health history.