Exam Quick Guide

Vitamin D testing measures the level of this essential substance in your blood. It is used to diagnose vitamin D deficiencies or to monitor treatment for a known deficiency.

The main function of vitamin D is to assist in the assimilation of calcium during bone germination. Maintaining adequate levels of vitamin D supports good for you bones. In addition, vitamin D has anti-inflammatory and other properties that play a role in maintaining normal musculus, immune, and nervous system functions.

Vitamin D blood testing can be used to cheque your levels so a deficiency can exist corrected. Less commonly, vitamin D testing may be used to detect vitamin D toxicity, a condition in which there is an excess of vitamin D in the body.

About the Test

Purpose of the test

Vitamin D testing is used to determine whether you have enough vitamin D in your body to back up normal bodily functions. An inadequate level of vitamin D is called a deficiency. A more balmy lack of vitamin D can be referred to every bit an insufficiency.

Your health care provider may order a vitamin D test in lodge to:

  • Screen for a possible deficiency or insufficiency if you have a hazard gene that increases the likelihood of having a low level of vitamin D. A risk factor is annihilation that makes it more likely for a health problem to occur.
  • Diagnose a vitamin D deficiency or insufficiency if you have symptoms that suggest low levels. Testing may likewise exist used to diagnose a rare vitamin D toxicity due to backlog intake of vitamin D supplements.
  • Monitor your vitamin D levels if you are existence treated for a previously detected deficiency.

What does the test measure?

Vitamin D is necessary for maintaining health. Information technology 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 office in helping the body absorb calcium, which makes it crucial to maintaining bone health. Inadequate levels of vitamin D tin can lead to abnormal bone development, os weakness, and hurting.

Unlike other vitamins, Vitamin D can be created in the human trunk. When your pare is exposed to straight sunlight, ultraviolet radiation converts a chemical in your peel 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 2 major forms of Vitamin D:

  • Vitamin D2 (ergocalciferol): Vitamin D2 is created in plants, such equally yeast or mushrooms. It is also available equally a supplement and in fortified foods.
  • Vitamin D3 (cholecalciferol): Vitamin D3 is generated in the peel when information technology is exposed to sunlight. It is also found in some beast-based foods and may be consumed in certain fortified foods or dietary supplements.

Both vitamin D2 and D3 need to go through chemical changes earlier existence 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:

  • 25-hydroxyvitamin D: In the liver, vitamin D is converted into 25-hydroxyvitamin D, which is also chosen 25(OH)D. Most of the fourth dimension, vitamin D levels will be tested by measuring blood levels of 25(OH)D. Testing 25(OH)D is considered the most accurate manner to measure how much vitamin D is in your body because 25(OH)D is the major grade of vitamin D circulating in the bloodstream.
  • ane,25-dihydroxyvitamin D: In the kidneys, 25(OH)D is converted into a hormone called active vitamin D or 1,25-dihydroxyvitamin D. Sometimes, health care providers may check your blood level of ane,25 dihydroxyvitamin D, which is likewise called one,25(OH)2nd.This substance is generally non used to detect inadequate vitamin D levels, but it may be measured in patients with abnormal calcium levels or kidney problems.

When should I get a vitamin D test?

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 claret exam for you if you lot are experiencing symptoms of a vitamin D deficiency, such as:

  • Weakening of the bones
  • Abnormal os development
  • Bone deformity
  • Bone pain
  • Muscle weakness or cramps
  • Seizures
  • Dental abnormalities

Sometimes vitamin D tests are used as screening tests for individuals at increased take a chance of a vitamin D deficiency. Screening tests are conducted before any symptoms occur. The post-obit are factors that may increase your adventure of developing a vitamin D insufficiency or deficiency:

  • Age over 65
  • Obesity
  • History of weight loss surgery
  • Osteoporosis
  • Reduced ability to brand vitamin D in the skin due to limited sun exposure, sunscreen use, or dark skin pigmentation
  • Digestive diseases that make information technology difficult to absorb nutrients from food, including celiac disease and Crohn's illness
  • Kidney and liver disease
  • Use of certain medications

Vitamin D tests may also be ordered if your health care provider suspects that you may take 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 as well much lord's day 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 basic 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 intendance provider who is familiar with your medical history is in the best position to determine whether you lot might benefit from vitamin D testing.

Finding a Vitamin D Test

How to get tested

Vitamin D testing is typically ordered past a health care provider and takes place in a medical setting like a physician's office, clinic, laboratory, or hospital.

Tin I take the test at home?

Several at-home exam kits are commercially available that allow y'all to provide a claret sample for vitamin D testing. Some kits test but your vitamin D levels, and others test vitamin D in combination with additional measurements, such as other vitamins and minerals or C-reactive poly peptide.

Vitamin D dwelling collection kits may exist purchased online and include the materials yous need to take a finger prick sample of claret that is returned past mail to the testing company to analyze. Your calm vitamin D test results are unremarkably reported to you via a secure online platform.

At-home testing tin be convenient and enable y'all to participate in your health care, but at-abode tests cannot replace working with a health care professional. If you have symptoms of an abnormal level of vitamin D, exist sure to share your concerns with your health intendance provider. If an at-home test detects a vitamin D deficiency, insufficiency, or toxicity, your medico will likely recommend retesting your vitamin D level to ostend the event.

How much does the test cost?

The toll of vitamin D blood testing depends on where y'all have the test taken, whether other tests are performed at the same time, and whether you have wellness care coverage.

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

Taking a Vitamin D Exam

A claret sample is used to measure your vitamin D level as ordered by a wellness care provider. A blood sample will usually be taken from your arm in a medical setting like a physician's function or hospital and analyzed in a medical laboratory.

Before the test

Usually, there are no special preparations required for vitamin D blood testing. Your wellness care provider will tell yous if whatsoever preparations are needed for your examination.

During the exam

Virtually ofttimes, a small blood sample is taken from a vein in your arm. The health care professional taking the sample may tie a ring around your upper arm to make your veins easier to locate. Then they disinfect a small patch of pare with an antiseptic wipe. Side by side, they insert a needle attached to a drove tube into your skin and withdraw a pocket-sized corporeality of blood.

After the exam

After your blood sample has been collected and the needle is withdrawn, yous may exist asked to use pressure to the site with a piece of gauze and then a bandage. This stops the site from haemorrhage and may prevent bruising. You volition exist able to resume your normal activities, including driving, immediately after the examination.

In that location are very few risks associated with a blood draw. You may accept slight bruising in the area where the blood sample was taken, especially if you do not maintain pressure on the wound for several minutes.

Vitamin D Test Results

Receiving test results

Vitamin D blood examination results are normally available within a few concern days. Your health care provider may call you with the results or request that y'all make an appointment to hash out them. Yous may too receive your results through a secure online patient portal or in the mail.

Interpreting test results

Your test report will include information about your level of vitamin D and the reference range used to translate your upshot. Reference ranges are the test upshot values that are considered optimal for wellness. Results that fall outside the reference range may signal a health consequence.

Reference ranges tin vary by laboratory. Additionally, some labs may break down your levels of vitamin D2 and D3, while other laboratories report the combined total.

Medical experts and organizations have differing opinions on the ideal levels of vitamin D. Generally, exam results can be used to distinguish betwixt an insufficiency, in which vitamin D amounts are only slightly outside of the ideal range, and a deficiency, which tin can cause more serious problems.

The table beneath summarizes the exam results, interpretations, and potential medical outcomes that experts consider when looking at a patient's 25-hydroxyvitamin D level:

Vitamin D Exam Results
Test Result Estimation Potential Medical Consequence
Deficient Vitamin D levels besides low to support salubrious bodily functions At that place is not enough calcium in the blood. Weakening of bones or painful bone problems may occur.
Bereft Vitamin D levels lower than the ideal reference range Most people are asymptomatic. There may be accelerated bone loss or increased run a risk of fracture.
Sufficient Vitamin D levels autumn within reference range At that place is an acceptable amount of vitamin D and no known risks for health problems.
Risk of toxicity Excessive amount of vitamin D in the trunk This can cause too much calcium to broadcast in the blood, which can lead to confusion, loss of appetite, vomiting, and musculus weakness.

Your health intendance provider can decide what your vitamin D exam result means for your health.

Are test results authentic?

Testing 25-hydroxyvitamin D is considered the most accurate way to measure whether your intake of vitamin D, both through sun exposure and diet, is adequate.

Yet, a number of factors are taken into business relationship when interpreting your vitamin D examination results, including differences in tests and laboratory procedures, your weight and skin pigmentation, and medical atmospheric condition like kidney failure which can impact the trunk's ability to apply vitamin D.

You can talk with your wellness intendance team to acquire more about the accurateness and significance of vitamin D testing in your specific example.

Do I demand follow-up tests?

Not all people who have abnormal levels of vitamin D require follow-up testing. If your vitamin D test shows an abnormal result, your health intendance provider will decide whether you demand additional testing based on several factors. These include your symptoms, the results of a physical examination, and how far outside the reference range your vitamin D level falls.

When vitamin D levels are very depression, more tests may be ordered. These may include echo vitamin D testing as well as tests of other substances, such as:

  • Calcium
  • Phosphorus
  • Alkaline metal phosphatase (ALP)
  • Parathyroid hormone (PTH)
  • Electrolytes
  • Blood urea nitrogen (BUN)
  • Creatinine
  • Tissue transglutaminase antibodies

If your vitamin D level is abnormally loftier, you may require additional tests, including:

  • Calcium
  • Parathyroid hormone (PTH)
  • Bones metabolic console (BMP)

X-rays or other imaging tests may be ordered for some patients with vitamin D levels outside the reference range. Imaging tests are helpful in assessing how abnormal vitamin D levels have impacted the bones.

If you lot are given treatment to bring your vitamin D levels into the normal range, repeat vitamin D testing and calcium levels may be used to monitor treatment response.

Questions for your doctor about test results

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

  • Do my vitamin D exam levels indicate a deficiency or insufficiency?
  • Do my exam results show that I have been taking too much vitamin D every bit a supplement?
  • Will boosted testing be needed?
  • Do my test results indicate that handling is needed?

Related Tests

Vitamin D testing in children

Vitamin D deficiency and insufficiency can be a problem in infants and children. Vitamin D deficiency tin cause a serious disease called rickets that affects os evolution. Rickets may result in skeletal deformities, impaired growth, brusque stature, and dental problems.

Vitamin D deficiency in childhood is more common in countries where a large portion of the population is malnourished. Even so, sure risk factors that increment the chances of vitamin D deficiency can occur in infants and children in whatsoever state and include:

  • Exclusive breastfeeding since breast milk has low vitamin D content
  • Lack of sunlight exposure, darker skin pigmentation, and sunscreen utilise
  • Diets that limit intake of vitamin D-fortified foods

Health care providers may order vitamin D testing for infants and children with symptoms of vitamin D deficiency, such every bit skeletal changes. Some health providers will also screen young patients without symptoms, such as exclusively breastfed infants, children whose skin is darkly pigmented who live in areas with low sun exposure, and children whose diets are low in vitamin D.

Related Content

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