To test or not to test — the ABC’s of vitamin D testing and treatment
Recommendations for people who choose to get vitamin D testing — and some
guidance for those who don’t
by Marcelle Pick, OB/GYN NP
How do I know if I need testing?
Today we know the prevalence of vitamin D
deficiency is widespread, and for this reason feel testing is easily justifiable
for all people. Everyone stands to benefit from knowing what their levels
are and, if not optimal, supplementing their vitamin D3 intake. But we also recognize
that for whatever reason, not everyone will choose to get tested.
Still, at the very minimum, people who have or are at higher risk of the following
health concerns should seriously consider getting their vitamin D levels tested:
- family history or personal history of cancer
- hypertension (high blood pressure)
- autoimmune conditions (such as lupus, ankylosing spondylitis, multiple sclerosis,
- PCOS (polycystic ovarian syndrome)
- diabetes mellitus (both types 1 and 2)
In addition, anyone who experiences symptoms of:
- musculoskeletal pain, including joint pain and low back pain
- muscle weakness
- poor balance
- systemic inflammation
What if I decide not to get tested?
As we explain at some length in our full article on
vitamin D, there is a wealth of health benefits to be enjoyed when we are
vitamin D replete. One way to get there knowingly is through periodic testing and
vitamin D supplementation. But if you choose not to get tested, all the benefits
of the sunshine vitamin are still available to you. You have two options:
Natural vitamin D production. The freest, most natural way is nature’s
own: through limited exposure of your skin to the sun. Without sunblock, your skin
can manufacture on average 10,000–15,000 IU vitamin D in a single “pinking”
exposure. But this route has its limitations, too. Most obviously, if your skin
is very, very light, or if you are at risk of or have a history of melanoma, or
if you’re fearful of sun exposure for any reason, this is not a workable option
for you. (Note that sunblock with an SPF of 15 or higher will block 100% of vitamin
D production.) In addition, sun exposure doesn’t work equally well for everyone.
It’s a given that the darker your skin, the more melanin pigment it contains,
and the more prolonged sunshine exposure you will need to produce adequate vitamin
D. What’s more, our inborn ability to manufacture vitamin D from sun exposure
tends to decrease as we age, too, and it’s been found that many elderly folks
do not manufacture vitamin D at all well. This is because as we age, the thickness
of our skin decreases linearly, along with the amount in the skin of the cholesterol-related
precursor to the vitamin D molecule. Recently it has also been found that people
who are obese do not as readily generate vitamin D in the skin.
Oral vitamin D supplements. Luckily, almost anyone in these groups can
benefit from taking oral vitamin D3. If you are among those at higher risk of vitamin
D deficiency and you decide not to have testing, we suggest you take 2000 IU oral
vitamin D3 supplementation daily. If after 6 weeks you’re not feeling
better, you may very well need more to achieve optimal levels. In this case you
will need testing and follow-up with a qualified healthcare practitioner to safely
achieve optimal levels.
Here is a list of certain populations who are at higher risk of vitamin D deficiency:
- Those who live above 35–40° latitude — you may only get enough radiation
from the sun between May and October in the Northern Hemisphere, and between October
and May in the Southern Hemisphere. (Visit the World Atlas website to check out your latitude!)
- Those who do not get out in the sun regularly, those who avoid it altogether, and
those who use SPF 15 or higher sunblock
- Dark-skinned people
- Elderly people
- Overweight/obese people
What specific test should I request from my healthcare provider?
You want to ask for the test that measures the circulating form of vitamin D: this
is referred to as 25[OH]D, or 25-hydroxyvitamin D.
Do I need to schedule my vitamin D test at a certain time, or together with other
Vitamin D testing is best done:
- at any time when you have not been exposed to UVB light for ~6 weeks, as in late
fall through late spring or summer
- after discontinuing vitamin D supplement use for at least 3 days
- when you are at least 4 hours fasting
- together with a test for serum calcium levels (an indicator for toxicity)
What levels are optimal when I get my vitamin D tested?
Most labs here in the US currently have a reference range of 20–100 ng/mL. As you
can see from the table below, we use a much narrower range at Women to Women!
Vitamin D levels — what’s really optimal?
Excessive vitamin D (see note on toxicity)
Proposed optimal range
Overt vitamin D deficiency
Many testing labs are currently reporting a twofold to threefold increase in the
number of vitamin D tests being ordered. But even now that many physicians agree
that everyone needs to get their levels checked, the risk here is that it you may
become just another number, where as long as you fall within the conventional
normal range, you’re told you’re just fine.
The reality is that you will not be deriving all the benefits of vitamin D unless
your levels are quite a bit higher than the norm. You may want to explain to your
practitioner, when talking about your blood test, that your goal is to reach into
the higher end of the conventional reference range. The mean value in the US is
between 25 and 30 ng/mL, so most people here have values that are well below optimal.
While the “normal” reference range is considered to be anywhere from
20–100 ng/mL, the latest scientific research shows the optimal range for health
maintenance is 50–70 ng/mL. At these higher levels numerous health benefits can
be gained — better bone strength, mood, energy, hormone performance, inflammation
reduction, cancer prevention, and more! (Visit the Grassroots Health website to download a
chart showing levels needed to provide preventive and healing benefits.)
For healing more serious medical conditions, some research is showing you may need
to keep your vitamin D level up even higher. If you have a serious medical condition
such as cancer, we urge you to work with a functional medicine practitioner to reach
and maintain the levels most helpful for you as an individual.
How much does a vitamin D test cost?
We wish there was an easier answer to this question, but the reality is that today
in the US, the cost of vitamin D testing can vary significantly. It could cost you
nothing to a minimal $25, to even more than $250, so you may want to bring the subject
up with your healthcare provider when you ask for testing. There are a number of
reasons for this variability. For instance, cost can be higher if the lab where
you get your test drawn does not perform vitamin D testing in-house, and has to
send your sample out. Costs are also higher at labs that have not automated their
vitamin D testing technology. In either case, testing can be labor-intensive and
thus more expensive.
If cost is a consideration for you, one option is to ask your healthcare provider
if she or he would be willing to negotiate with a lab for lower-cost “volume”
testing for their patients (including you). Not only will you benefit from this,
but it could encourage your practitioner to test more patients who are at risk of
vitamin D deficiency, and those patients, too, will be better able to afford the
testing for this widespread nutrient deficiency.
Different insurance carriers and policies can vary widely in coverage for the test
as well. If you have a health insurance, you can check with your health insurance
representative for policy specifics.
Another alternative that works for some people, particularly those without insurance
or where the policy coverage is limited, is to search for an on-line lab that performs
vitamin D testing. Here’s roughly how this works: you pay on-line; they ship
you the kit; you bring the kit to your healthcare practitioner and have the sample
drawn in their office; then you forward the sample to the on-line lab. Results can
be copied to both you and your provider, and you can work with your provider from
there for interpretation and follow-up. (If you use an on-line kit, just make sure
you’re working with a credible lab — credentials may be easier to validate
if the lab is based in the US.)
Is testing worth it? What do I get in return for my investment?
To answer the first part of that question: Yes, we think so! Put simply, testing
will inform you and your healthcare provider on the status of your serum 25-hydroxyvitamin
But more importantly, that information is invaluable for determining your next step
— what to do to get your levels up to optimal. You are one among millions,
if yours are not: using very conservative estimates, some 25% of adults in the US
are deficient. That means the health of at least 12 million people could be profoundly
enhanced on the basis of this simple test, together with easy, safe, affordable
vitamin D supplementation. Doesn’t that make sense?
Recall that optimal vitamin D levels will give you optimal calcium absorption, put
the breaks on bone-breakdown, reduce blood pressure, decrease risk of various cancers,
retard the progression of inflammatory factors like CRP and inflammatory conditions
such as osteoarthritis and diabetes, and reduce incidence of autoimmune illness.
And that’s just a start. We hope this information helps you carefully entertain
the value of testing!
How do I know how much vitamin D to take to get replete?
How much supplemental vitamin D3 to take depends on how much is in your blood. And
how much your body needs to get your levels higher differs from person to person.
We recommend 1000–2000 IU/day unless you are working with a qualified functional
medicine practitioner or nutritionist with regular testing in follow-up.
If you are deficient, more than this will likely be necessary, but any supplementation
above and beyond 2000 IU daily should only be done in conjunction with periodic
testing and under the watchful guidance of a qualified healthcare professional.
Again, if you have a serious medical problem, testing and regular follow-up will
Should I be worried about vitamin D toxicity? How can I prevent
vitamin D toxicity?
For most otherwise healthy people who choose not to test for vitamin D levels, it’s
generally okay to supplement with 2000 IU vitamin D3 (cholecalciferol) daily, at
least between the fall through the spring months, and even in the summertime 2000
IU per day should be fine if you do not get unprotected sun exposure.
However, we do want you to be aware that there are some precautions regarding vitamin
D supplementation. If you have any health condition that predisposes you
to high calcium in the blood (hypercalcemia),you should not take vitamin
D except under the watchful care of a healthcare provider. These conditions include
but are not limited to:
- granulomatous disease
- Lyme disease
- kidney disease
It also includes anyone taking the diuretic known as hydrochlorothiazide
(HCTZ), a “water pill” drug used to treat high blood pressure and fluid
retention caused by a range of conditions, including heart disease.
What are the symptoms of vitamin D toxicity? Can someone be just
hypersensitive to vitamin D?
Rarely, an individual may ingest too much vitamin D, which puts them at risk for
a reaction from vitamin D hypersensitivity or toxicity. But most people with vitamin
D toxicity do not experience symptoms — which is why we do not at this time
recommend using more than 2000 IU per day without regular testing and follow-up.
Symptoms of hypersensitivity may be dizziness, and signs of toxicity may include
serious stomach upset, vomiting and excessive thirst. If a woman has any concerns
or reactions suspected she should stop use immediately and contact the doctor.
The symptoms of too much vitamin D (hypervitaminosis D) are connected with
the consequences of having too much calcium in the blood (hypercalcemia).
This occurs once the kidneys’ ability to eliminate calcium is exceeded.
Note that this is not a common problem — thankfully, vitamin D toxicity is
rare. Most healthy people would have to take a great deal of oral vitamin D before
they would reach toxic levels. Here is a list of the clinical manifestations
of vitamin D toxicity:
- weight loss
At our clinic, whenever we prescribe more than 2000 IU vitamin D daily for a patient,
we also prescribe regular retesting, and typically request that their blood calcium
levels be checked at the same time, just so there is no question of toxicity. See
For maintenance after boosting and ideal range is fully achieved:
- Fall/winter months = 2000 IU vitamin D3 daily after ideal level
- Spring/summer months = 1000 IU vitamin D3 daily, with 15–30 minutes
of daily sun exposure to limbs without sunscreen at safe-sun times of day (avoiding
11:00 AM – 2:00 PM), then regular retesting again in the mid to late fall.
Maintenance retesting notions to consider after reaching ideal range:
- For those initially found deficient — retesting at least every 6 months
- For those initially found insufficient — retesting at least annually
- For those initially found not ideal — retest with fasting lipid profiles every
one to two years
What about retesting? Do I need it?
This will depend on your medical or health condition, and how much vitamin D supplementation
you are taking or if you are being prescribed vitamin D therapeutically. If you
are found to be deficient and/or you are supplementing at doses higher than 2000
IU daily, we recommend retesting within 2 weeks to 2 months after initiating supplementation.
Once you attain vitamin D repletion, you can refer to the box below on how to keep
your levels optimal.
How can I maintain my vitamin D levels once I get them up to where I want to be?
That’s a wonderful question! The answer will vary, according to your age,
skin tone, where you live (latitude), the seasons, and your lifestyle (indoors or
outdoors, sunscreen protection, and other aspects of the way you live). It will
also depend on other risk factors for vitamin D deficiency, and you may want to
modify accordingly. Again, the best way to know is to get tested periodically! Here’s
what we do in Maine, where the UVB rays are only strong enough (290–315 nm) between
May and September to convert the precursor molecule in the skin to provitamin D3.
Our Personal Program is a great place to start
The Personal Program promotes natural hormonal balance with nutritional supplements,
our exclusive endocrine support formula, dietary and lifestyle guidance, and optional
phone consultations with our Nurse–Educators. It is a convenient, at-home
version of what we recommend to all our patients at the clinic.
If you have questions, don't hesitate to call us toll-free at
1-800-798-7902. We're here to listen and help.
Related to this article:
References & further reading
on vitamin D testing and treatment
Is vitamin D deficiency casting a cloud over
Are tanning beds a safe source
of vitamin D?
Last Modified Date: 04/20/2011
Principal Author: Marcelle Pick,OB/GYN NP