Doctor’s Data Vitamin D Blood Spot

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Doctor’s Data Laboratories
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Receptor sites are like catchers mitts – in baseball, the pitcher throws the ball to the catcher. The way our hormones get into our cells is by being ‘caught’ in the bloodstream by a receptor site. Estrogen goes into estrogen receptor sites and then goes inside that cell. Testosterone goes into testosterone receptor sites. Insulin, melatonin,… all of our hormones get inside the cells by being caught by a receptor site. If there is no receptor site on the surface of a cell for a particular hormone, that hormone cannot get into that cell.

There are only two substances I know of for which there are receptor sites on every cell of your body. Only two. They are thyroid hormone because thyroid hormone is the ‘thermostat’ in every cell of your body that determines how hot that cell runs (that’s called your metabolism, and Vitamin D. Every cell in your body requires Vitamin D. Every cell. That’s why it’s called ‘the sunshine vitamin’, it brings life to every cell in your body. So if you have low Vitamin D levels, what cell may not function correctly? Every cell! Any cell! That’s why Vitamin D is the most important of all nutrients for the body because every cell needs it.

25-Hydroxyvitamin D, known for its role in bone health and calcium absorption, also appears to affect immune function, neurodegenerative and cardiovascular issues, and other conditions. Vitamin D occurs in two forms—D3 is obtained from animal diet sources and through sun exposure, and D2 is obtained through vegetable diet sources. Both forms of the vitamin are used to fortify various foods and in supplements.



25-Hydroxyvitamin D Total

25-Hydroxyvitamin D2

25-Hydroxyvitamin D3


This test is useful for:

Alzheimer’s Disease

Bone Health

Calcium Absorption

Cardiovascular Disease


Immune Function


Multiple Sclerosis

Neurocognitive Dysfunction


Rheumatoid Arthritis

Type 2 Diabetes


Specimen: blood spot

Detailed Information:

25-Hydroxyvitamin D is the major circulating form of vitamin D. It occurs in two forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol), and is the precursor of the active form (1,25-dihydroxyvitamin D). Because of its long half-life, measurement of total 25-Hydroxyvitamin D (D2 plus D3) provides the best assessment of patient vitamin D status and includes vitamin D derived from diet, supplements and exposure to UVB light, such as sunlight. Vitamin D is best known for its role in calcium and bone metabolism, but emerging research indicates that low levels of vitamin D may be associated with increased risk of some cancers, type 2 diabetes, multiple sclerosis, cardiovascular disease, rheumatoid arthritis, depression, Alzheimer’s disease, infections, preeclampsia, cesarean deliveries and neurocognitive dysfunction. Vitamin D regulates the expression of a vast array of genes in tissues including immune cells, the vasculature, muscle and reproductive organs. Vitamin D insufficiency is common and deficiency can have adverse health effects at any stage of life. Many testing methods do not differentiate between the two forms of vitamin D, and only total concentrations are reported. This LC/MS QQQ method is sensitive and specific for both vitamin D2 and D3, and each form is measured and reported independently.


You also have the option of scheduling a test interpretation consultation with one of our Consultants Consultation charges are based on the amount of time. We recommend scheduling a 15-minute test interpretation consultation.

*Please read the following prior to placing your lab test order*


      • All sales are final and no refunds will be afforded and you waive any rights to charge-back your purchase with your credit card processor.
      • does not participate in, take assignment, or accept any private insurance. We do not provide super bills and cannot assist with claim resolution for laboratory tests or consultations.
      • Orders for this test are accepted from the United States only. To inquire about international orders, please email:  This test is not available in Mexico, Iran, North Korea, Cuba, Russia or Ukraine.
      • is unable to ship test kits to the state of New York as per state laws.
      • is unable to ship lab kits to P.O. boxes. Please use a residential or business address.
      • Some lab providers fill out requisition forms ahead of time with client information. To avoid confusion when processing orders, if you are ordering lab kits for multiple people, please place a separate order for each person.
      • After you order a test kit, completing the test is your responsibility.
      • This test does NOT include a test interpretation consultation.  If you would like to schedule a test interpretation consultation, please contact: once you have received your test results.
      • Test interpretation consultations DO NOT include personalized recommendations. Personalized recommendations are available within our Discovery, Essentials, and Premier programs.
      • Once has received your test results, the results will be uploaded to your HIPAA compliant client portal and you will receive an email instructing you how to access them.
      • Please contact with questions.

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