Vitamin D Test

Vitamin D Test Serum

The Most Common Vitamin Deficiency in the United States

Vitamin D is primarily responsible for maintaining normal levels of calcium and phosphorus in the blood, which are essential for bone mineralization. However, it also has a significant impact on the expression of over 2,000 genes involved in cellular proliferation, differentiation, apoptosis, and angiogenesis. The immune-modulating effects of Vitamin D are profound and its deficiency is associated with many common and serious diseases, including certain cancers, diabetes, cardiovascular disease, and osteoporosis.

MosaicDX’s Vitamin D Test is a useful tool in assessing Vitamin D levels, determining if sun exposure and dietary intake are adequate, and evaluating the likelihood of malabsorption or liver disease.

Dried Blood Spot, Serum
Turnaround Time: 1-2 weeks

Turnaround times are estimates. Detailed order tracking is available in the MosaicDX Portal.

Vitamin D Test Serum

What Patients Might Benefit from Vitamin D Testing?

There are a number of symptoms and conditions associated with Vitamin D deficiency:

  • Autoimmune Diseases
  • Birth Defects
  • Cardiovascular Disease 
  • Chronic Bone, Muscle, or Joint Pain
  • Chronic Fatigue
  • Cognitive Impairment
  • Depression and Mood Disorders
  • Diabetes Type I & II
  • Hypertension
  • Inflammatory Bowel Diseases
  • Low Blood Calcium
  • Multiple Sclerosis
  • Osteoporosis/Osteomalacia
  • Periodontal Disease
  • Rheumatoid Arthritis
  • Schizophrenia
  • Stroke


Why Assess Vitamin D Levels?

Vitamin D deficiency has been linked to increased risk for many common and serious diseases, including some common cancers, diabetes, cardiovascular disease, and osteoporosis. Deficiency is also prevalent in infants who are solely breastfed and who do not receive Vitamin D supplementation. Adults of all ages who have darker skin (increased skin melanin) or who always wear sun protection or limit their outdoor activities, such as homebound elderly persons, are also prone to Vitamin D deficits.

Sunlight exposure is a natural source of Vitamin D and has been shown to prevent many chronic diseases. Low levels of Vitamin D are also linked to seasonal depression, particularly during the winter months with less sunlight exposure. Vitamin D can also be obtained through diet and supplementation, although there are few food sources (fatty fish, fish liver oil, and eggs) that contain it naturally. Fortified foods may contain synthetic forms of Vitamin D, which are less potent and have a shorter lifespan in the body.

MosaicDX’s Vitamin D Test is a serum or dried blood spot analysis that quantitates 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 metabolites. The metabolite 25-hydroxyvitamin D is the major circulating form of Vitamin D in the body and the best indicator of a patient’s true vitamin status. The major biologic function of Vitamin D is to maintain the normal blood levels of calcium and phosphorus involved in bone mineralization. Vitamin D also influences expression of more than 2,000 genes, including those responsible for regulation of cellular proliferation, cell differentiation, apoptosis, and angiogenesis. The immune-modulating effects of Vitamin D are profound, as evidenced by the many conditions that are associated with Vitamin D deficiency.

Learn More About the Vitamin D Test: Explore FAQs


The metabolite 25-hydroxyvitamin D is the major circulating form of Vitamin D in the body and the best indicator of a patient’s true vitamin status.

  • 25-hydroxyvitamin D2
  • 25-hydroxyvitamin D3

Sample Reports

The Vitamin D Test report can help to determine if sun exposure is adequate, if dietary Vitamin D is sufficient, and to assess the likelihood of malabsorption or liver disease.

Test Prep and Instructions

MosaicDX offers patient-friendly sample collection kits that simplify testing. Our kits include visual, step-by-step instructions for test preparation and sample collection, personalized shipping cards, and pediatric collection bags if needed. With MosaicDX, patients can easily collect samples for testing with confidence and accuracy.

Frequently Asked Questions

The ordering process for MosaicDX tests starts with your healthcare practitioner assessing your symptoms and recommending the most appropriate test.

Once a test has been recommended, collection kits can be conveniently ordered and delivered straight to your doorstep. If you already have a collection kit, you can register your test and begin the process at your convenience.

It is important to carefully follow the collection instructions and include all required information about yourself and your specimens when registering your test. When your specimens are collected, you can use the prepaid shipping materials provided in your kit to ship them to MosaicDX. Your results will be accessible online via the MosaicDX portal. We recommend scheduling an appointment with your healthcare practitioner to discuss your results and develop a plan for your healthcare

If you are located outside of the U.S., our customer service team can assist you in finding a distributor in your country. In countries where a distributor is not required, you can place an order through our international patient ordering site. Please note that all international shipping costs must be paid prior to shipping the kit.  

The 2000-2004 NHANES provided the most recent data on the Vitamin D nutritional status of the U.S. population. Approximately 9 percent of the pediatric population, representing 7.6 million U.S. children and adolescents, were 25(OH)D deficient and 61 percent, representing 50.8 million U.S. children and adolescents, were 25(OH)D insufficient. Generally, younger people had higher Vitamin D levels than older people, males had higher levels than females, and non-Hispanic whites had higher levels than Mexican Americans, who in turn had higher levels than non-Hispanic blacks. Depending on the population group, 1-9 percent had levels <11 ng/mL , 8-36 percent had levels <20 ng/mL, and the majority (50-78 percent) had levels <30 ng/mL.

The Vitamin D Receptor (VDR) is a nuclear hormone receptor that is activated by the active form of Vitamin D, calcitrol. VDR is expressed by most cells in every organ of the body. More than 2,000 genes are regulated by VDR activation.

The primary role of Vitamin D is to regulate blood levels of calcium and phosphorus by promoting absorption in the intestines and reabsorption in kidneys. Calcium and phosphorus levels are important for bone mineralization and growth as well as for the prevention of hypocalcemic tetany. Vitamin D is also an important immune regulator. It promotes phagocytosis, anti-tumor activity, and immunomodulary functions that play a role in autoimmune disease.

Different states have regulations that define the scope of practice for practitioners. It is the practitioner’s responsibility to abide by these rules. Check with your state board of health to determine any restrictions related to laboratory testing. Please note, Mosaic Diagnostics does not offer testing in New York. 

Once you have opened your account, you have the options of ordering kits to stock in your office or drop-ship kits directly to your patients through your MosaicDX portal.   

Watch our short tutorial videos on how to conveniently  

Already have a kit? Watch this video on how to place an order for your patient using a kit from your inventory.   

Please refer to your test’s specific Test Preparation and Instructions for more information regarding the potential effects of medications, foods, and supplements on this test. 

You make also consult your healthcare provider prior to making any changes to your medications.

Visit the payment information page for an overview of payment options and procedures along with insurance coverage overview.

NOTE: Insurance coverage for testing is based on several factors such as the type of procedure, diagnosis, and insurance policy guidelines. Patients are encouraged to contact their insurance company to check for coverage and to provide the procedure codes (CPT codes) and diagnostic codes (ICD-10 codes). The CPT codes can be found on the billing information page, while ICD-10 codes are provided by the practitioner.

Mosaic Diagnostics offers written interpretations within test reports and complimentary consultations with our clinical educators for qualified practitioners. To schedule a consultation, simply sign in to your MosaicDX account and book a consultation online. 

We encourage all patients to discuss results with your practitioner.

Our Resources tab also contains educational materials that you may find useful, we also offer MosaicEDGE workshops for qualified practitioners to better understand the fundamentals of lab testing.

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