Normal Vitamin D Levels, 1, 25-Hydroxy (Calcifediol)
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Vitamin D, 25-Hydroxy Test
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Vitamin D, 25-Hydroxy Test

Vitamin D, 25-Hydroxyvitamin D (Calcifediol)

$35.00

Vitamin D #82306 

SKU: 081950 Category: Tags: ,

Vitamin D, 25-Hydroxy (Calcifediol)

What this test measures
This test measures 25-hydroxyvitamin D (calcifediol), the primary circulating form of vitamin D and the most accurate marker of overall vitamin D status in the body.

It reflects vitamin D obtained from:

  • Sun exposure

  • Diet

  • Supplements

and how effectively vitamin D is being stored and made available to tissues.

Why vitamin D matters far beyond bone health
Vitamin D functions more like a regulatory hormone than a simple vitamin. It influences hundreds of genes involved in immune balance, brain function, inflammation control, and cellular repair.

Adequate vitamin D is essential for:

  • Nervous system stability and neuroprotection

  • Immune regulation (calming overactive immune responses)

  • Inflammation control

  • Hormone signaling and receptor sensitivity

  • Mood, sleep regulation, and stress tolerance

Deficiency is common—even in people who eat well or supplement—and often goes unnoticed.

Vitamin D and the brain
Vitamin D plays a direct role in:

  • Neurotransmitter regulation

  • Neuroinflammation control

  • Protection against excitatory overstimulation

Low levels are frequently associated with:

  • Sleep disruption

  • Anxiety or inner tension

  • Sensory sensitivity

  • Cognitive slowing or brain fog

  • Poor stress resilience

In neurodevelopmental and neuropsychiatric presentations, vitamin D deficiency can amplify existing biochemical vulnerabilities rather than act as a single cause.

Vitamin D and immune balance
Vitamin D helps the immune system respond appropriately—strong when needed, quiet when not.

Low vitamin D may contribute to:

  • Chronic immune activation

  • Poor recovery after infection

  • Heightened inflammatory signaling

  • Increased sensitivity to environmental triggers

This is particularly relevant in individuals with histories of:

  • Autoimmune tendencies

  • Chronic inflammation

  • Mold or toxic exposures

  • Recurrent infections

Why vitamin D is included in the Walsh Comprehensive Biotype Panel
Within a Walsh-informed framework, vitamin D is considered a foundational regulator, not an isolated variable.

Vitamin D status influences:

  • How the nervous system responds to stress

  • Inflammatory tone affecting neurotransmitter balance

  • Expression of symptoms that overlap with methylation, copper imbalance, or oxidative stress

Without knowing vitamin D status, other biochemical findings can be misleading or incomplete.

Low vs high vitamin D — both matter

  • Low levels may impair immune control, brain signaling, and recovery capacity

  • Excessively high levels (usually from unsupervised supplementation) can disrupt calcium balance and increase oxidative stress

Testing ensures vitamin D support is appropriate, targeted, and safe.

Why testing is important (not guessing)
Vitamin D requirements vary widely between individuals based on:

  • Genetics

  • Body composition

  • Sun exposure

  • Absorption efficiency

  • Inflammatory burden

Symptoms alone do not reliably predict vitamin D status. Testing provides clarity before making long-term decisions.

Who should consider this test

  • Individuals with sleep, mood, or stress-related symptoms

  • Those with inflammatory, immune, or neurological concerns

  • Anyone with limited sun exposure or long-term supplementation

  • Individuals pursuing a Walsh-based biochemical assessment

Testing details

  • Blood test

  • Measures 25-hydroxyvitamin D (calcifediol)

  • Performed through Labcorp

  • After purchase, a Labcorp requisition will be provided for specimen collection

What You Receive

  • A LabCorp order (no doctor’s visit required)

  • Testing at any LabCorp location nationwide

  • Results typically within 2–3 business days

  • Optional review and interpretation through Second Opinion Physician services

  • Guidance on optimal ranges, not just “normal” lab values

How to Use This Test

  1. Add the test to your cart and complete checkout.

  2. You will receive a LabCorp requisition form by email.

  3. Visit any LabCorp site for a quick blood draw.

  4. Results will be delivered securely through your patient portal.

  5. You may schedule a follow-up consult for interpretation and a personalized plan.

Optimal Levels

While labs often report wide “normal” ranges, research and clinical practice commonly support:

  • 50–90 ng/mL as an optimal functional range

  • Levels below 30 ng/mL indicate deficiency

  • Levels below 20 ng/mL significantly increase risk of infection, mood issues, and bone loss

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