Vitamin D Test

Having blood tests to measure the amount of vitamin D in your blood is the only way to know if you’re getting enough vitamin D or not. The blood test you need is called a 25(OH)D blood test.

You can get a blood test at your doctors or you can do an in-home test or get a test at a laboratory. All of these methods of testing should give you accurate results. In-home tests are easy to use and involve pricking your finger to take a small blood sample and sending this away to a laboratory for testing.

Your tests results will show whether you’re getting enough vitamin D or not, and whether you may need to take supplements or expose your skin to the sun more. Different organizations in the United States recommend different ideal vitamin D levels. The Vitamin D Council suggests that a level of 50 ng/ml is the ideal level to aim for.

How do I get tested?

There are three ways to get tested:

1. Ask your doctor for a vitamin D test. Be specific and ask for a 25(OH)D test. There is another type of blood test for vitamin D, called a 1,25(OH)₂D test, but the 25(OH)D test is the only one that will tell you whether you’re getting enough vitamin D.
2. Order an in-home test. These tests are sent to your home. You prick your finger and put a drop of blood on to some blotter paper. You send the paper to a laboratory to be tested. In-home test kits are a convenient option for those who prefer to take a vitamin D test in the comfort of their own home.
3. Order a test online and get blood work done at a laboratory. In the United States, there are a few websites in which you purchase an in-home vitamin D test online, and then, you attend the laboratory closest to you. These tests are more expensive than in-home tests.

What do the results mean?

When you get your test results you will see a number in units of ng/ml, for example, 50 ng/ml. These are the units that health professionals in the United States use. Elsewhere in the world, vitamin D blood test results are given in units of nmol/l.

To convert a test result measured in nmol/l to one measured in ng/ml, divide the nmol/l number by 2.5. For example, 50 nmol/l is the same as 20 ng/ml (50÷2.5).

To convert a test result measured in ng/ml to one measured in nmol/l, multiply the ng/ml number by 2.5. For example, 20 ng/ml is the same as 50 nmol/l (20 x 2.5).

These are the ranges that different organizations in the United States use to say whether you’re severely lacking in vitamin D (deficient), mildly lacking in vitamin D (insufficient) or whether you’re getting enough vitamin D (sufficient):

Vitamin D 25(OH)D guidelines from organizations

The Vitamin D Council suggests that a level of 50 ng/ml is the ideal level to aim for. This is why the Council recommends that adults take 5,000 IU/day of vitamin D supplement in order to reach and stay at this level.

The Endocrine Society recommends taking a vitamin D supplement of around 2,000 IU/day to reach and stay above a level of 30 ng/ml. This is what the Endocrine Society recommends as the ideal level to aim for. Lastly, the Food and Nutrition Board recommends 600 IU/day of vitamin D supplement because they believe 20 ng/ml is the ideal level to aim for.

What should you do based on your test results?

• If you tested low and want a higher level, you need to get more sun exposure or take a larger daily supplement.
• If you tested and are right where you want to be, continue your supplement and sun exposure routine. Keep in mind that your level in the summer is probably higher than in the winter, with more sun and UVB. So you may need to supplement more in the winter than in the summer to have the same vitamin D level.
• If you tested high and want a lower level, you need to take a smaller daily supplement.

You do not want to have a level over 100 ng/ml and in fact anything over 150 ng/ml is considered toxic. Go to the following pages for more information about your results, supplementation, and sun exposure. All three ways of getting tested should give you an accurate result.

Vitamin D level test results

If you have had your vitamin D levels tested, it’s important to understand what the results mean, and what action you might need to take. The blood test that measures vitamin D is called a 25(OH)D blood test. The results of the blood test can tell you whether you’re getting too little, too much or the right amount of vitamin D. This will help you to decide whether to take more or less supplement, or expose your skin to the sun more. When you get your test results you will see a number in units of ng/ml, for example, 50 ng/ml. These are the units that health professionals in the United States use. Elsewhere in the world, vitamin D blood test results are given in units of nmol/l.

• To convert a test result measured in ng/ml to one measured in nmol/l, multiply the ng/ml number by 2.5. For example, 20 ng/ml is the same as 50 nmol/l (20 x 2.5).
• To convert a test result measured in nmol/l to one measured in ng/ml, divide the nmol/l number by 2.5. For example, 50 nmol/l is the same as 20 ng/ml (50÷2.5).

Here is a quick summary of what different levels mean and what the levels may mean for your health and what to do below. Note that everybody is different and not everybody achieves the same levels after supplementing with the same amounts. The tables below show on average how much a supplement regimen might raise your blood levels, but you can think of the amounts listed as more of a prediction than a guarantee. This is why you may consider checking your levels twice per year or more, to see if you need to increase or decrease your dosage.

My level is between 0-10 ng/ml

You’re severely deficient in vitamin D by every standard out there, including the Institute of Medicine, the Endocrine Society and the Vitamin D Council. With a vitamin D level in this range, your health is at risk. You may have low blood calcium levels which can lead to softening of your bones. With very low vitamin D levels you may also have less strength in your muscles and have difficultly moving. If you want to raise your blood levels starting from 10 ng/ml, you can take the following action (based on an average body weight of 150lbs):

My level is between 10-20 ng/ml

By Endocrine Society and Vitamin D Council standards, you’re still deficient in vitamin D. According to the Institute of Medicine, you’re mildly deficient, or insufficient, in vitamin D. If you’re African American or Hispanic American you’re likely to be in this range. With vitamin D levels in this range you’re more likely to develop osteoporosis and your bones may be affected because your body isn’t absorbing enough calcium. This means you’re more likely to fracture or break bones and more likely to have a fall. You may also have high levels of parathyroid hormone in your body. Parathyroid hormone controls the levels of calcium and phosphorus in your body and too much can affect your bones. If you want to raise your blood levels starting from 15 ng/ml, you can take the following action (based on an average body weight of 150lbs):

My level is between 20-30 ng/ml

According to the Vitamin D Council, you’re deficient in vitamin D. According to the Endocrine Society, you’re insufficient. By the Institute of Medicine’s standards, you’re getting enough vitamin D. If you’re Caucasian American, you’re likely to have a vitamin D level in this range. With a vitamin D level in this range you’re less likely to have health problems than when vitamin D is at lower levels. However, your body may still be producing too much parathyroid hormone and not fully absorbing calcium, which can affect your bones. Research shows that levels above 30 ng/ml may be more likely to prevent bone problems such as fractures. If you want to raise your blood levels starting from 25 ng/ml, you can take the following action (based on an average body weight of 150lbs):

My level is between 30-40 ng/ml

According to the Vitamin D Council, you’re still not quite sufficient in vitamin D, though your levels are better than most people’s. By Endocrine Society and Institute of Medicine standards, you’re getting enough vitamin D. The good news is, with vitamin D levels in this range, your body is absorbing calcium well and you should have the right levels of parathyroid hormone. This means strong and healthy bones. In some research studies, vitamin D levels in this range have been shown to reduce your risk of developing cancer and improve your immune system, which fights infection. If you want to raise your blood levels starting from 35 ng/ml, you can take the following action (based on an average body weight of 150lbs)

My level is between 40-50 ng/ml

According to most standards, including the Vitamin D Council, Endocrine Society and Institute of Medicine, you are getting enough vitamin D! These are the levels of vitamin D humans evolved with. If you spent an entire year exposing your full naked body to the sun at the equator, these are the levels of vitamin D you would have. In modern times, these are the levels that hunter gatherers still living traditional outdoor lifestyles in Africa have. At these levels, vitamin D is working well to control the level of parathyroid hormone and calcium in your body. If you’re breastfeeding you will have vitamin D in your breast milk to pass on to your baby. Some research studies suggest that these levels of vitamin D are linked to a reduced risk of some cancers and better heart health and circulation. Research also suggests that this level of vitamin D helps to give you a strong immune system to fight infection. If you want to raise your blood levels starting from 45 ng/ml, you can take the following action (based on an average body weight of 150lbs):

My level is between 50-60 ng/ml

You’re getting the right amount of vitamin D by the standards set by the Vitamin D Council and Endocrine Society. The Institute of Medicine, however, doesn’t feel there is enough evidence to say that having a level higher than 50 ng/ml is of any benefit. Some vitamin D researchers believe that these levels are the best to aim for, though more research is needed to be sure about this.

My level is between 60-80 ng/ml

You’re getting the right amount of vitamin D by the standards set by the Vitamin D Council and Endocrine Society. The Institute of Medicine, however, doesn’t feel there is enough evidence to say that having a level higher than 50 ng/ml is of any benefit. The Vitamin D Council considers this the “high-normal” range. Research studies have shown that you can achieve these levels just by exposing your skin to the sun, so it’s believed that these are certainly healthy and natural levels. There isn’t currently enough research to know if there is any benefit to having vitamin D levels this high, instead of levels between 40 ng/ml and 60 ng/ml. However, there is no known danger in keeping your vitamin D level in this 60-80 ng/ml range.

My level is between 80-100 ng/ml

You are still within the normal range according to testing laboratories and the Endocrine Society. The Institute of Medicine, however, doesn’t feel there is enough evidence to say that having a level higher than 50 ng/ml is of any benefit. These levels are just above what you can naturally achieve by just exposing your skin to the sun. In other words, you can’t achieve these levels without taking a supplement. There isn’t currently enough research to know if there is any benefit to having levels this high. However, there is no known danger in maintaining levels in this 80-100 ng/ml range.

My level is between 100-150 ng/ml

Although these levels aren’t toxic and aren’t usually harmful, they are thought to be too high. There are no known benefits to having a vitamin D level over 100 ng/ml. A study by a group of researchers in Utah found that levels over 100 ng/ml are linked to a slight increased risk of developing an irregular heart beat called atrial fibrillation. You should take steps to lower your levels to below 100 ng/ml , unless you are under the supervision of your doctor. To lower your levels, stop taking supplements. After three months, test your vitamin D levels and adjust the amount of supplement you take once your test results show your level has dropped back down to the normal range.

My level is greater than 150 ng/ml

You have toxic levels of vitamin D, which can be harmful to your health. You should take steps to lower your levels to below 100 ng/ml unless you’re under the supervision of your doctor. To lower your levels, stop taking supplements. After three months, test your vitamin D levels and adjust the amount of supplement you take once your test results show your level has dropped back down to the normal range.

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