Vitamin D Test

The CNS Vitamin D Test uses a conventional ELISA-based technology to determine levels of 25-Hydroxyvitamin D and other metabolites in serum or plasma.

Vitamin D deficiency can be a serious problem and does not have very obvious symptoms, but increases susceptibility to other more serious conditions. Maintaining Vitamin D levels protects the body from a wide range of diseases including viruses, cardiovascular disease, bone disease including osteoporosis, rickets and osteomalacia, autoimmune disease (such as multiple sclerosis and rheumatoid arthritis), strokes, nervous system disorders (such as Parkinson’s Disease) and type 1 and 2 diabetes. Depression and breast, prostate and colon cancer have also been linked to Vitamin D deficiency.



Frequently Asked Questions

What is Vitamin D?
Vitamin D, a fat-soluble vitamin, is more appropriately categorized as a prohormone which is a collective term for a group of seco-steroids. Vitamin D is metabolised by hepatic 25-hydroxylase into 25-hydroxyvitamin D and by renal 1α- hydroxylase into the active form 1, 25- dihyroxyvitamin D. Essentially, vitamin D maintains the levels of calcium and phosphate which in turn is needed for normal bone mineralisation, muscle contraction, nerve conduction and general cellular function. More specifically 1, 25-dihydroxyvitamin D is a strong steroid hormone that has a crucial role in calcium homeostasis, bone metabolism, cell growth and replication.
Why do I need vitamin D?
Your body must have vitamin D to absorb calcium and promote bone growth. Too little vitamin D results in soft bones in children (rickets) and fragile, misshapen bones in adults (osteomalacia). You also need vitamin D for other important body functions. Vitamin D deficiency has now been linked to breast cancer, colon cancer, prostate cancer, heart disease, depression, weight gain, and other maladies. These studies show that people with higher levels of vitamin D have a lower risk of disease, although they do not definitively prove that lack of vitamin D causes disease -- or that vitamin D supplements would lower risk.
What causes Vitamin D deficiency?
There are a number of factors which can cause a vitamin D deficiency: • Deficient production • Decreased input due to seasonal lack of exposure to sunlight • Anything that interferes with the penetration of solar ultraviolet radiation into the skin will diminish the cutaneous production of Vitamin D3 • Dietary intake is low • Marked decrease in the capacity of the human skin to produce vitamin D in the elderly • Impaired absorption due to kidney or digestive diseases • Inherited polymorphisms which affect vitamin D absorption.
How much vitamin D do I need?
The current recommended daily dose of vitamin D is 200 IU for people up to age 50, 400 IU for people aged 51 to 70, and 600 IU for people over age 70.
I spend a lot of time outdoors. Don't I get enough vitamin D from sun exposure?
Not likely. As people age, they often lose the ability to make Vitamin D3. In fact, Americans age 50 and older are believed to be at increased risk of developing vitamin D deficiency. Furthermore, season, geographic latitude, time of day, cloud cover, smog, and sunscreen can greatly affect UV ray exposure and consequently alter vitamin D synthesis.
Why test for Vitamin D deficiency?
Vitamin D deficiency can be a serious problem and does not have very obvious symptoms. It increases susceptibility to other more serious conditions. Maintaining Vitamin D levels protects the body from a wide range of diseases including viruses, cardiovascular disease, bone disease including osteoporosis, rickets and osteomalcia, autoimmune disease (such as multiple sclerosis and rheumatoid arthritis), strokes, nervous system disorders (such as Parkinson’s Disease) and type 1 and 2 diabetes. Depression and breast, prostate and colon cancer have also been linked to Vitamin D deficiency.
How does the test work?
CNS uses a conventional ELISA based technology to determine the total concentration of both 25- hydroxyvitamin D2 and 25-hydroxyvitamin D3 (25(OH)D). The method has been calibrated against the gold standard LC-MS/MS method, demonstrating excellent agreement with external quality assurance.
Will the test results tell me if I need more vitamin D?
Yes. As part of your regular blood test, your health practitioner should order a test for 25-hydroxyvitamin D (25-OHD). It is commonly accepted that adults with a 25-OHD level of less than 15 ng/mL or 37.5 nmol/L (depending on the units reported by a lab) need more vitamin D. A 2002 study found that 42% of African-American women of childbearing age had vitamin D levels below 15 ng/ml. The U.S. National Institutes of health notes that 25-OHD levels over 30 ng/mL are optimal, and that there is insufficient data to support recommendations for higher levels. The Vitamin D Council considers the ideal 25-OHD level to be between 40 ng/mL and 70 ng/mL.
What can be done? - How can I get enough vitamin D?
While thirty minutes of sun exposure to the face, legs, or back, without sunscreen twice a week should give you plenty of vitamin D, the American Academy of Dermatology recommends against getting vitamin D from unprotected exposure to sunlight. This is due to the fact that too much direct sun exposure might also expose you to potentially dangerous levels of cancer-causing UV radiation. However, you can also get vitamin D from foods or from supplements, so in the absence of adequate sun exposure, these are alternative options.
What can be done? - Which foods contain vitamin D?
Surprisingly few foods contain vitamin D -- unless it's added to the food. That's because your body is built to get vitamin D through your skin (from sunlight) rather than through your mouth (by food). These include: • Oily fish • Cod liver oil •Milk or yogurt • Beef or calf liver • Egg yolks • Cheese • Fortified breakfast cereals • Mushrooms exposed to ultraviolet light to increase vitamin D
What can be done? - My multiple vitamin formula contains vitamin D2. Is that the same as vitamin D3?
Two forms of vitamin D are used for nutritional supplementation. They are ergocalciferol (vitamin D2) and cholecalciferol (Vitamin D3). Vitamin D2 is derived from fungal and plant sources while most of our Vitamin D3 is produced in our bodies by the action of sunlight on 7-dehydrocholesterol in the skin. Vitamin D3 is superior to vitamin D2, as it has been shown to raise blood levels 70% better than D2. It is therefore recommended to choose supplements which contain vitamin D3. To ensure you are supplementing the right amount it is best to follow the guidance of a professional.
What are the sample requirements & test turnaround?
Simply collect a finger-prick blood sample using the components provided in the Sample Collection Pack and send to the Cambridge Nutritional Sciences Laboratory using the pre-paid envelop supplied. Results are available within 10-15 working days. CNS participates in the DEQAS external quality assessment scheme for Vitamin D testing. The CNS Vitamin D test has not been verified for use with clients under the age of 18. Although it can still be used in some cases, under 18s may have different blood protein levels which may affect the results of most Vitamin D tests currently available.