Vitamin D blood test
One marker, often low in Australian women despite the sun. Know your level, and know what your laboratory's range actually means.
The vitamin D blood test measures 25-hydroxy vitamin D, the storage form that reflects how much vitamin D you have built up from sunlight and food over the previous several weeks. It is $49, and a KnowLuna doctor can request it for you at no extra charge. Add a 20-minute video consult for +$59 if you want it explained. Collect at an accredited Australian centre, or choose a home kit or a nurse visit at checkout (options below).
What it measures
- 25-hydroxy vitamin D (25-OH D): the form laboratories measure to assess vitamin D status, reported in nanomoles per litre (nmol/L). It is the standard test, and the one meant whenever a doctor says "check your vitamin D".
Vitamin D matters for calcium absorption and bone strength, and it is involved in muscle function and immune function. Most of ours comes from sunlight on skin rather than from food, which is why levels move with the season, your working hours and how much skin you have uncovered.
Who it's for
Testing makes most sense when there is a reason to expect a low result, or when a level would change what you and your doctor do next.
- Little sun exposure: indoor work, night shifts, limited mobility, or long southern winters.
- Naturally darker skin, which produces vitamin D more slowly for the same sun exposure.
- Clothing that covers most of the skin.
- Pregnancy, planning pregnancy, or the months after birth.
- Bone health concerns, including a family history of osteoporosis or a fracture from a minor fall.
- Ongoing fatigue, muscle aches or bone pain that you and your doctor are working through.
- Gut conditions that affect absorption, such as coeliac disease.
It is for adults aged 18 and over. If none of the above applies and you feel well, a routine vitamin D test often adds little, and your doctor may say so.
What you'll learn, and what you won't
You will learn where your level sits against the Australian bands used by laboratories, in plain English, along with what a low result usually reflects at this time of year and in your circumstances.
What one number cannot do is explain your symptoms on its own. Tiredness, aches and low mood have many causes, and a mildly low vitamin D may be a bystander rather than the reason. A blood test is one input to a doctor's assessment, not a diagnosis on its own. If your level is low, what happens next is a conversation with a doctor who knows your history.
Reference ranges and what they mean
| Typical Australian band | Level (25-OH D) | What it usually means |
|---|---|---|
| Sufficient | 50 nmol/L or above at the end of winter (60 to 70 at the end of summer) | Adequate for bone health in most adults. Levels are usually a little higher at the end of summer. |
| Mild deficiency | 30 to 49 nmol/L | Common in winter and in people with limited sun exposure. Your doctor weighs it against your bone health, symptoms and sun exposure. |
| Moderate deficiency | 12.5 to 29 nmol/L | Low enough that your doctor will usually act on it and look for a cause. |
| Severe deficiency | Below 12.5 nmol/L | Carries a risk of bone softening (osteomalacia) and needs medical follow-up. |
Ranges vary by laboratory; your report shows the range your lab uses. The bands above follow the Australian and New Zealand position statement on vitamin D (2012), which Australian laboratories and Pathology Tests Explained (RCPA) still use.
When Medicare covers vitamin D testing, and when it does not
Vitamin D was once one of the most-ordered tests in Australia, and after a change to the Medicare Benefits Schedule the rebate was restricted from 1 November 2014 to specific clinical situations rather than general screening. In practice, a rebate is available when your doctor requests the test for a recognised clinical reason, such as signs of osteoporosis or osteomalacia, a calcium or parathyroid disorder, malabsorption, chronic kidney disease, deeply pigmented skin or very limited sun exposure. Feeling tired, or wanting to know your level, does not qualify, and the cost falls to you.
KnowLuna is self-pay either way, with the price shown before you order and no surprise gap. If you think your situation might attract a rebate, your own GP is the cheaper route, and we would rather tell you that than not.
When to do this test
Any time of day, and no fasting is needed. Timing across the year is what matters most: vitamin D is typically at its lowest at the end of winter and early spring, and at its highest at the end of summer, so a late-winter result is the most useful test of whether you run low.
If you are already taking vitamin D on your doctor's advice, retesting is usually done after about three months, since the level moves slowly. There is little value in repeating it every few weeks.
How it works
- Order online. Either upload the request your own doctor has signed, or a KnowLuna doctor requests the test for you at no extra charge.
- Collect at an accredited centre near you, or choose a home kit or a nurse visit (options below). Any time, no fasting.
- Results are usually ready within a few business days, explained in your account, with an optional consult if you want to talk them through.
Choose how you collect
Every option is the same accredited test and the same report. Pick what suits you at checkout; the fee, if any, is added to either pathway price.
A quick draw at an accredited pathology collection centre near you. Usually under ten minutes. Included.
Lancet kit posted to you with an Express return satchel. If the lab cannot test your sample we send a replacement kit at no charge.
A near-painless device draws a small sample from the upper arm, with far fewer failed samples than a finger-prick. Express return satchel included.
A registered nurse comes to your home or workplace for a standard blood draw. Metro areas of capital cities; other locations on request.
Common questions
What are the symptoms of low vitamin D in women?
Low vitamin D is often silent. When symptoms do appear they are usually vague: tiredness, muscle aches or weakness, and bone or lower back pain. Severe, long-standing deficiency affects bone strength. Because these symptoms overlap with low iron and thyroid problems, doctors commonly check those markers at the same time.
What is a normal vitamin D level in Australia?
Australian laboratories generally regard 50 nmol/L or above at the end of winter as sufficient for bone health. Below that is graded as deficiency: 30 to 49 nmol/L is mild, 12.5 to 29 is moderate and below 12.5 is severe. Your report shows your laboratory's exact bands, and your doctor reads the number alongside the season and your circumstances.
Is a vitamin D test covered by Medicare?
Only in defined clinical situations. Since the Medicare Benefits Schedule was tightened, a rebate applies when your doctor requests the test for a recognised reason such as signs of osteoporosis or osteomalacia, a calcium or parathyroid disorder, malabsorption or very limited sun exposure, rather than as general screening. Feeling tired, or simply wanting to know your level, does not qualify. Ordering it yourself through KnowLuna is self-pay, at $49.
Do I need to fast for a vitamin D test?
No. Vitamin D testing does not require fasting and can be collected at any time of day. If it is being taken with other tests, follow the preparation instructions for those, since some panels do require fasting. Your request form and confirmation email tell you exactly what to do.
How often should vitamin D be checked?
For most people with a normal result and no risk factors, repeat testing adds little. If your level was low, three months is the usual interval, because vitamin D changes slowly. Late winter is the most informative time of year to check, since that is when Australian levels are at their lowest.
Sources and further reading
- Medical Journal of Australia: Vitamin D and health in adults in Australia and New Zealand, position statement (2012)
- Medicare Benefits Schedule: item 66833, vitamin D testing criteria
- Healthdirect: vitamin D deficiency
- Healthdirect: vitamin D test
- Better Health Channel: vitamin D
General information only, not medical advice. A test result is one input to a doctor's assessment, not a diagnosis on its own, and every abnormal result is followed up by a KnowLuna doctor. If your symptoms are severe or sudden, see a doctor promptly. Read our medical disclaimer.
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Worth knowing before winter ends.