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Vitamin D 25 Hydroxy Level

When Should I Get A Vitamin D Test

Vitamin D Levels and Risk of Mortality

Vitamin D testing is ordered to determine if a deficiency, insufficiency, or toxic level of vitamin D is present or to monitor treatment for a previously diagnosed deficiency.

Your health care provider may order a vitamin D blood test for you if you are experiencing symptoms of a vitamin D deficiency, such as:

  • Weakening of the bones
  • History of weight loss surgery
  • Reduced ability to make vitamin D in the skin due to limited sun exposure, sunscreen use, or dark skin pigmentation
  • Digestive diseases that make it difficult to absorb nutrients from food, including celiac disease and Crohnâs disease
  • Kidney and liver disease
  • Use of certain medications

Vitamin D tests may also be ordered if your health care provider suspects that you may have abnormally high vitamin D levels, known as vitamin D toxicity. This occurs as a result of taking too much vitamin D in supplements rather than from too much sun exposure or dietary intake.

Excess vitamin D in supplement form may cause your body to absorb more calcium from food and to reabsorb calcium from the bones into the blood. This results in excess calcium in the blood, also known as hypercalcemia, which can lead to symptoms like fatigue, confusion, bone pain, nausea and vomiting, frequent urination, and kidney problems.

A health care provider who is familiar with your medical history is in the best position to determine whether you might benefit from vitamin D testing.

The Iom And Es Recommended Desirable 25ohd Levels

Mean 25OHD level range in different ethnicities in this study:c
Infants: 2.4â37 20â19 years: 18.7â33.1
Children and adolescents: 8.2â36.1 > 50 years: 21â28.9
Postmenopausal women and elderly men: 9.2â48.6 c
6. Fractures âBecause available trials often administered relatively high doses of vitamin D, serum 25OHD concentrations varied considerably. Although some studies suggested that serum 25OHD concentrations of approximately 40 nmol/L are sufficient to meet bone health requirements for most people, findings from other studies suggested that levels of 50 nmol/L and higher were consistent with bone health. Given that causality has been established between changes in serum 25OHD levels and bone health outcomes, information from observational studies can be useful in determining the doseâresponse relationship.â 25OHD between 30 and 40 ng/ml âconsistent with the threshold for hip and non-vertebral fracture prevention from a recent meta-analysis of double-blind randomized controlled trials with oral vitamin Dâ
25OHD levels Mean/median 25OHD level range in studies: 7.3â55 cMean 25OHD levels not available in the IOM or ES reports but derived from retrieving the full text of quoted studies. Mean/median 25OHD level range in studies: 24.8â44.9

Assay Standardization And The Vitamin D Standardization Program

Challenges in all of the above assay methods methods are clear, and a high level of technical expertise is required for performing manual test and designing any vitamin D method. External proficiency testing schemes , or external quality assessment schemes , such as DEQAS, and the vitamin D quality assessment service offered by the College of American Pathologists , are primarily based on the methodology being used in the respective laboratories, and results obtained vary widely. Examination of the quarterly reports issued by DEQAS that are based on data received from around 1000 laboratories, measuring four unknown samples, reveal wide variations in the mean serum 25OHD level derived by each specific methodology for the same sample of 8 to 16âng/mL . The histogram also reveals a consistent trend for the interassay differences between the mean for methodologies reported, varying between 2.5 and 16âng/mL. The closest to target value were those values obtained by LC-MS/MS, followed by HPLC . The above-reported 25OHD levels derived with each methodology are based on means values obtained from a few dozen to several hundred laboratories, and underestimate variations on individual patient measurements. At present, there exist no practical regulated and reference procedures for clinical measurement of serum 25OHD level. The choice of a particular method by a laboratory more often depends on available expertise, economics, and profitability.

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What Is Vitamin D 25 Hydroxy

Vitamin D helps regulate calcium and phosphorus. If you suspect that your calcium levels are low or if you have symptoms of Vitamin D deficiency then, you ought to order a Vitamin D test. Symptoms can be rickets in children, bone weakness, softness, and osteomalacia. Older individuals, those with dark skin and those who live in colder climates with minimal exposure to sunlight are also recommended to regularly test their Vitamin D levels as they are at risk of deficiencies.

Vitamin D has two forms. Each form has its own specific test. The 25-hydroxyvitamin D, found in the blood, is the inactive precursor to the active form 1,25-dihydroxyvitamin D. The first form is what is normally tested to assess the status of Vitamin D.

The 25,hydroxy vitamin D test is used to screen for vitamin D deficiency. Vitamin D plays an important role in preventing osteoporosis and ensuring a proper growth and healthy teeth and bones. In recent years, research has shown that vitamin D also plays a role in maintaining other aspects of overall health. Research is ongoing regarding its potential role in protecting against an array of conditions inclding diabetes, cancer and multiple sclerosis.

According to a report from the National Center for Health Statistics, about 1 in 3 people in the US do not get enough vitamin D.

Serum 25 D Levels And Risk Of Recurrent Bppv


The patients were divided into two groups according to the recurrence or nonrecurrence of BPPV. showed that patients with recurrent BPPV had lower serum levels of 25 D compared with nonrecurrent BPPV . As a continuous variable, 25 D was associated with decreased risk of recurrent BPPV in the univariate model. Multiple-logistic regression analyses adjusted for age, sex, BMI, season, diabetes mellitus, hypertension, hyperlipidemia, smoking, drinking, VAS score, regular exercise habit, and different semicircular canals showed that 25 D was still associated with decreased risk of recurrent BPPV . In addition, as a categorical variable, the results suggested that vitamin D deficiency was associated with recurrent BPPV with the ORs of 5.16 .

Comparisons of serum 25 D levels between patients with recurrent BPPV and de novo BPPV

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Causes Of Vitamin D Deficiency

Vitamin D deficiency can occur for a number of reasons:

You don’t consume the recommended levels of the vitamin over time. This is likely if you follow a strict vegan diet, because most of the natural sources are animal-based, including fish and fish oils, egg yolks, fortified milk, and beef liver. Here are the best vitamin d foods for vegetarians.

Your exposure to sunlight is limited. Because the body makes vitamin D when your skin is exposed to sunlight, you may be at risk of deficiency if you are homebound, live in northern latitudes, wear long robes or head coverings for religious reasons, or have an occupation that prevents sun exposure. Duirng the winter, vitamin D deficiency can be more prevalent because there is less sunlight available.

You have dark skin. The pigment melanin reduces the skin’s ability to make vitamin D in response to sunlight exposure. Some studies show that older adults with darker skin are at high risk of vitamin D deficiency.

Your kidneys cannot convert vitamin D to its active form. As people age, their kidneys are less able to convert vitamin D to its active form, thus increasing their risk of vitamin D deficiency.

Your digestive tract cannot adequately absorb vitamin D. Certain medical problems, including Crohn’s disease, cystic fibrosis, and celiac disease, can affect your intestine’s ability to absorb vitamin D from the food you eat.

Why Is A 25

Your doctor may request a 25-hydroxy vitamin D test for several different reasons. It can help them figure out whether too much or too little vitamin D is causing bone weakness or other abnormalities. It can also monitor people who are at risk for having a vitamin D deficiency.

Those who are at high risk of having low levels of vitamin D include:

  • people who dont get much exposure to the sun
  • babies who are breastfed only
  • people who have had gastric bypass surgery
  • people who have a disease that affects the intestines and makes it difficult for the body to absorb nutrients, such as Crohns disease

Your doctor may also want you to do a 25-hydroxy vitamin D test if theyve already diagnosed you with a vitamin D deficiency and want to see if treatment is working.

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Can I Take The Test At Home

Several at-home test kits are commercially available that allow you to provide a blood sample for vitamin D testing. Some kits test only your vitamin D levels, and others test vitamin D in combination with additional measurements, such as other vitamins and minerals or C-reactive protein.

Vitamin D home collection kits may be purchased online and include the materials you need to take a finger prick sample of blood that is returned by mail to the testing company to analyze. Your at-home vitamin D test results are usually reported to you via a secure online platform.

At-home testing can be convenient and enable you to participate in your health care, but at-home tests cannot replace working with a health care professional. If you have symptoms of an abnormal level of vitamin D, be sure to share your concerns with your health care provider. If an at-home test detects a vitamin D deficiency, insufficiency, or toxicity, your doctor will likely recommend retesting your vitamin D level to confirm the result.

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Difficulties In Predicting 25ohd Level Based On Known Genetic Or Lifestyle Predictors

25-Hydroxyvitamin D assay standardization and vitamin D guidelines paralysis

Despite characterization of genetic and lifestyle predictors of circulating serum 25OHD levels, it remains very difficult to interpret the specific impact of any one single factor because of the complex interaction between predictors, which in some instances may vary in opposing directions leading to counterintuitive findings. Modeling studies suggest that lifestyle factors combined can explain up to 50% of variability in 25OHD levels . In a study of 664 elderly individuals vitamin D intake or supplements and baseline levels accounted for 24% of variability in serum 25OHD levels achieved. Although current vitamin D guidelines by IOM and ES take age, gender, and reproductive status into consideration, none has factored in lifestyle and genetics into their recommendations for desirable levels, with the exception of the Australian guidelines that take season into account.

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Vitamin D In Phase Iii Osteoporosis Registration Trials

The majority, if not all, pivotal phase III randomized trials included intake of calcium and vitamin D as the standard of care in both placebo and intervention arms, and several excluded subjects with low vitamin D levels at screening. However, a careful scrutiny of the information provided in the relevant publications describing these trials, detailed in Table ,- reveals the scarcity of information available regarding the subjects’ vitamin D status at trial entry, the actual average dose of vitamin D taken, mean 25OHD level achieved, and type of vitamin D assay used in the few studies that measured 25OHD level after study entry.- Thus, although the efficacy of the currently approved therapies is often stated to be in light of such supplemental use, it is not clear what the vitamin D nutritional status was in subjects included in these trials. Indeed, an entry criterion for vitamin D level was mentioned in only four of 26 trials, and baseline serum 25OHD level were reported in only four. One study specified both, and a vitamin D level was not measured at study completion in any of the reported trials.


To date, little is known about the vitamin D nutritional status in the majority of subjects enrolled in the registration trials for most U.S. Food and Drug Administration -approved osteoporosis therapies.

How Much Does The Test Cost

The cost of vitamin D blood testing depends on where you have the test taken, whether other tests are performed at the same time, and whether you have health care coverage.

The costs of testing may include an office visit, a blood draw fee, and charges from the laboratory analyzing your blood sample. These costs are usually covered by insurance when the test is ordered by your health care provider. However, you may wish to check with your health insurance company to learn whether you are responsible for a deductible or copay.

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Vitamin D Toxicity And Adverse Health Outcomes

Vitamin D toxicity is characterized by hypercalcemia concomitant with hypervitaminosis D, rather than by an absolute level of serum 25OHD. The reason is that hypercalcemia occurs at widely varying levels of 25OHD, although usually above 120 to 150âng/mL., Patients may have levels of serum 25OHD above 100âng/mL and up to 150âng/mL without associated hypercalcemia., , Vitamin D toxicity is generally rare in clinical practice in the modern era, despite use of increasingly higher doses of daily or intermittent vitamin D supplementation, and is usually the result of errors in manufacturing, formulation, or prescription, and more likely to be seen with large bolus doses . This has been reported, both in children and adults, in the setting of an unrecognized intake that is several hundred-fold higher than allowed by the recommended daily allowance., The IOM report concluded that doses of vitamin D up to 10,000âIU/day are unlikely to be associated with toxicity in adults, whereas daily doses exceeding 50,000âIU/day for weeks to months are associated with hypercalcemia. The Drugs and Therapeutic Committee of the Pediatric Endocrine Society recently completed a review on the risk of vitamin D toxicity in children on supplementation, concluding that it was only noted at a total cumulative intake of 240,000 to 4,500,000âIU of vitamin D.

What Does The Test Measure

Best Vitamin D

Vitamin D is necessary for maintaining health. It helps your body absorb minerals like calcium, magnesium, and phosphorus from your diet. Vitamin D also helps maintain proper levels of calcium, phosphate, and parathyroid hormone in your blood.

Vitamin D plays an important role in helping the body absorb calcium, which makes it crucial to maintaining bone health. Inadequate levels of vitamin D can lead to abnormal bone development, bone weakness, and pain.

Unlike other vitamins, Vitamin D can be created in the human body. When your skin is exposed to direct sunlight, ultraviolet radiation converts a chemical in your skin into an active form of vitamin D. Vitamin D can also be obtained through the diet, including from fortified or vitamin-enriched foods and vitamin supplements.

There are two major forms of Vitamin D:

  • Vitamin D2 : Vitamin D2 is created in plants, such as yeast or mushrooms. It is also available as a supplement and in fortified foods.
  • Vitamin D3 : Vitamin D3 is generated in the skin when it is exposed to sunlight. It is also found in some animal-based foods and may be consumed in certain fortified foods or dietary supplements.

Both vitamin D2 and D3 need to go through chemical changes before being able to be used by the body. These changes occur in the liver and the kidneys and convert vitamin D into measurable substances called 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D:

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How Long Can You Take 50 000 Iu Of Vitamin D

50,000 IU capsules are available by prescription only. If your blood levels are exceptionally low, you may need higher doses that should be used under the direction of a healthcare provider. In patients with vitamin D levels less than 20 ng/mL, start with 50,000 IUs of vitamin D3 once a week for 6 to 8 weeks.

How Can I Test My Vitamin D At Home

Everlywell Vitamin D Test Everlywell is an online company that offers a variety of at-home test kits and ships within the U.S. An Everlywell vitamin D test involves a person taking a finger-prick blood sample. Results will show whether a person’s vitamin D levels are elevated, adequate, or suboptimal.

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Assay Variations Impact On Care And The Vitamin D Standardization Program

Although serum 25OHD is the best index of nutritional vitamin D status, its measurement to define desirable vitamin D levels is limited by large variations incurred by the various methodologies used to date. Such variations by far exceed the differences in desirable 25OHD levels defined by IOM and ES.

What Is A 25

What are the prognostic values of 25-hydroxyvitamin D3 levels at diagnosis and follow-up?

Vitamin D is a nutrient that the body makes on exposure to sunlight. It is also present in some foods, such as oily fish and egg yolk. Vitamin D performs several important roles throughout the body. For example, it helps the body absorb calcium to maintain bone health. Doctors use blood samples to carry out the test.

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What Are The Signs And Symptoms Of Vitamin D Deficiency

Severe lack of vitamin D in children causes rickets. Symptoms of rickets include:

  • Incorrect growth patterns due to bowed or bent bones.
  • Muscle weakness.
  • Deformities in joints.

This is very rare. Children with a mild vitamin deficiency may just have weak, sore and/or painful muscles.

Lack of vitamin D isnt quite as obvious in adults. Signs and symptoms might include:

However, you may have no signs or symptoms of vitamin D deficiency.

Questions For Your Doctor About Test Results

You may wish to ask your doctor or other health care provider questions about your vitamin D test results, such as:

  • Do my vitamin D test levels indicate a deficiency or insufficiency?
  • Do my test results show that I have been taking too much vitamin D as a supplement?
  • Will additional testing be needed?
  • Do my test results indicate that treatment is needed?

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