✓Standard Care

Is Vitamin D Testing Worth It?

Q: Is vitamin D testing covered by Medicare in Australia?

Yes, vitamin D testing is covered by Medicare when ordered by a GP with clinical indication—meaning you have symptoms, risk factors for deficiency, or are monitoring response to treatment. Routine screening without clinical indication is not covered and contributes to overtesting.

Q: How often should I test vitamin D?

If you're at high risk, annual testing is reasonable, ideally at end of winter when levels are lowest. If you're supplementing due to deficiency, your GP will typically retest after 3 months to check response. Once levels are stable, ongoing testing may not be needed—maintenance supplementation can continue without repeated tests.

Q: Can I have too much vitamin D?

Yes, though toxicity is rare and requires sustained high-dose supplementation (typically >10,000 IU/day for months). Toxicity doesn't occur from sun exposure. Symptoms include nausea, vomiting, weakness, and kidney problems. Levels generally need to exceed 250 nmol/L for toxicity. This is why testing before high-dose supplementation is wise.

The sunburnt country paradox: 23% of Australians are vitamin D deficient despite abundant sunshine. Understanding when testing makes sense—and when it doesn't—could save you money and unnecessary worry.

Published 8 January 2026 · Updated 19 January 2026 · 9 min read

23%

of Australian adults are vitamin D deficient (<50 nmol/L)—climbing to 40%+ in southern states by end of winter

Source: [1]

The Short Answer

It depends—and the evidence is shifting. For high-risk groups (elderly, dark skin, limited sun exposure, malabsorption), vitamin D testing is guideline-backed and actionable. But 2024 guidelines suggest against routine screening in healthy adults under 75. The nuance matters: know your risk factors before ordering the test.

The Australian Vitamin D Paradox

How can a country known for beaches and sunshine have widespread vitamin D deficiency? The answer lies in how modern Australian life actually unfolds:

Indoor lifestyles

Most Australians work indoors during peak UV hours (10am-2pm)—exactly when vitamin D synthesis is most efficient

Sun protection success

Slip, slop, slap has successfully reduced skin cancer, but SPF 30+ blocks 95-99% of UVB needed for vitamin D synthesis

Southern latitude winters

Melbourne, Hobart, and Adelaide have UV levels too low for adequate vitamin D synthesis from May to August

Changing demographics

Increasing diversity means more people with darker skin who need 3-6x longer sun exposure for equivalent synthesis

The Numbers (ABS 2022-24)

23% of Australian adults are vitamin D deficient (<50 nmol/L)^[1]
40%+ of adults in Victoria, Tasmania, SA are deficient by end of winter
Up to 50% of Australians may have inadequate levels (<75 nmol/L) in winter
Higher rates in office workers, elderly, those with dark skin, and people who cover for religious/cultural reasons
Note: Evidence suggests overtesting is common—4.5 years of MBS data showed significant inappropriate vitamin D testing^[2]

Who Actually Benefits from Testing?

This is where nuance matters. Not everyone needs a vitamin D test—but some people genuinely benefit from knowing their levels:

Risk Factor	Why It Matters
Adults 75+ years	2024 Endocrine Society guidelines suggest empiric supplementation; testing confirms baseline^[3]
Osteoporosis or at-risk	Vitamin D essential for calcium absorption and bone health; testing guides supplementation
Dark skin	Melanin reduces vitamin D synthesis; need 3-6x longer sun exposure for equivalent production
Limited sun exposure	Shift workers, housebound, institutional care, religious/cultural dress that covers skin
Malabsorption conditions	Coeliac disease, Crohn's, IBD, gastric bypass significantly reduce vitamin D absorption
Obesity (BMI 30+)	Vitamin D is fat-soluble and sequestered in adipose tissue; higher doses often needed
Taking certain medications	Anticonvulsants, glucocorticoids, some HIV medications affect vitamin D metabolism
Pregnant women	2024 guidelines suggest empiric supplementation during pregnancy^[3]

What 2024 Guidelines Actually Say

The 2024 Endocrine Society Clinical Practice Guideline represents a significant shift in thinking about vitamin D:^[3]

Key 2024 Recommendations

Against routine screening: No evidence supporting routine 25(OH)D testing in general population, including those with obesity or dark complexion
Against empiric supplementation in healthy adults under 75: Evidence doesn't support supplementation above dietary reference intake for disease prevention
For empiric supplementation in specific groups: Adults 75+, pregnant women, children 1-18, those with high-risk prediabetes
No clear optimal level established: The guideline notes no clear evidence defining optimal target level for disease prevention^[3]

This doesn't mean testing is never useful—it means targeted testing based on risk factors, not blanket screening.

Understanding Your Results

Vitamin D is measured in nanomoles per litre (nmol/L). Australian laboratories generally use these reference ranges:^[2][4]

Below 30 nmol/LDeficient

Associated with increased risk of bone disease (osteomalacia, rickets). Supplementation typically recommended—often higher-dose 'loading' protocol.

30-50 nmol/LInsufficient

Mild deficiency. Supplementation or increased sensible sun exposure typically suggested. Most benefits plateau above this level.

50-75 nmol/LAdequate

Sufficient for bone health according to most Australian guidelines. No strong evidence for additional benefit above 50 nmol/L.

Above 75 nmol/LOptimal (debated)

Some practitioners prefer this level, but evidence for health benefits above 50 nmol/L is mixed. Toxicity rare below 250 nmol/L.

The 'Optimal' Level Debate

There's genuine scientific disagreement about what level is 'optimal':

Conservative View (RACGP, 2024 Endocrine)

50 nmol/L is sufficient for bone health
No clear evidence for benefit above 50 nmol/L
Focus on deficiency prevention, not optimisation
Concern about overtesting and medicalisation^[2][3]

Optimal Function View

75-100 nmol/L preferred by many practitioners
Epidemiologic data shows associations at higher levels
Considers muscle function, immunity, mood
Individualised targets based on symptoms^[5]

The honest answer: Evidence for health benefits is strongest when correcting deficiency (<50 nmol/L). Above that, the picture becomes murkier, with most health gains confined to very low levels.^[2]

When to Test: Timing Matters

Vitamin D levels fluctuate significantly with the seasons, especially in southern Australia:

Risk Factor	Why It Matters
End of winter (Aug-Sep)	Levels at their lowest—testing here captures your nadir and identifies true deficiency
End of summer (Feb-Mar)	Levels at peak—useful if you want to see your 'best case' or check if summer sun is sufficient
During supplementation	Test 3 months after starting—allows time for levels to stabilise and shows treatment response

Southern vs Northern Australia

If you live in Melbourne, Hobart, or Adelaide (latitude 34-43°S), UV levels from May to August are insufficient for adequate vitamin D synthesis regardless of sun exposure. You're essentially dependent on stores built up over summer or supplementation.

In Brisbane, Darwin, and northern Australia, year-round synthesis is possible with sensible sun exposure.^[4]

What to Expect from Your GP

Good news: When testing is appropriate, your GP will know exactly what to do:

If deficient (<30 nmol/L): High-dose supplementation protocol (often 3,000-4,000 IU/day or weekly megadose), retest in 3 months
If insufficient (30-50 nmol/L): Moderate supplementation (1,000-2,000 IU/day), sensible sun exposure advice
If adequate: Maintenance dose during winter if at-risk, sun exposure guidance for your skin type
Medicare rebate: Covered when ordered by GP with clinical indication (symptoms, risk factors, monitoring treatment)

Is It Worth the Cost?

✗ Probably Skip If...

You're a healthy adult under 75 with no risk factors^[3]
You tested in the last 6 months (unless treating deficiency)
You have good outdoor sun exposure and no symptoms
You're already taking appropriate maintenance supplements

✓ Worth Considering If...

You're 75+ years (though empiric supplementation may be sufficient)^[3]
You have dark skin and limited sun exposure
You have symptoms: fatigue, muscle weakness, bone pain, frequent infections
You have osteoporosis or are at high risk of fracture
You have a malabsorption condition (coeliac, Crohn's, IBD, gastric bypass)
You live in southern Australia and work predominantly indoors

The Bottom Line

Vitamin D testing is valuable for the right people—but 'right people' is narrower than you might think.

The 2024 evidence suggests moving away from routine screening toward targeted testing in those with genuine risk factors: elderly, dark skin, malabsorption, limited sun exposure, or symptomatic.

If you're a healthy adult under 75 without risk factors, the evidence for testing (or supplementation beyond dietary intake) is weak. If you're in a high-risk group, testing provides actionable information that guides treatment.

The Australian paradox of sunshine and deficiency is real—but the solution isn't universal testing. It's knowing whether you are at risk.

Frequently Asked Questions

Yes, vitamin D testing is covered by Medicare when ordered by a GP with clinical indication—meaning you have symptoms, risk factors for deficiency, or are monitoring response to treatment. Routine screening without clinical indication is not covered and contributes to overtesting.

If you're at high risk, annual testing is reasonable, ideally at end of winter when levels are lowest. If you're supplementing due to deficiency, your GP will typically retest after 3 months to check response. Once levels are stable, ongoing testing may not be needed—maintenance supplementation can continue without repeated tests.

Yes, though toxicity is rare and requires sustained high-dose supplementation (typically >10,000 IU/day for months). Toxicity doesn't occur from sun exposure. Symptoms include nausea, vomiting, weakness, and kidney problems. Levels generally need to exceed 250 nmol/L for toxicity. This is why testing before high-dose supplementation is wise.

The paradox is explained by lifestyle: most Australians work indoors during peak UV hours (10am-2pm), sun protection effectively blocks UVB needed for synthesis, and southern states have insufficient UV in winter. Darker skin, obesity, and malabsorption conditions compound the issue. Australian life doesn't automatically mean adequate vitamin D.

This is genuinely debated. Most Australian guidelines consider 50 nmol/L sufficient for bone health, and the 2024 Endocrine Society guideline found no clear evidence for optimal targets above this. Some practitioners prefer 75-100 nmol/L, but evidence for benefits at higher levels is mixed. Your GP will advise based on your circumstances and symptoms.

It depends on your situation, location, and skin cancer risk. For most Australians, a combination of sensible sun exposure (a few minutes of midday sun on bare skin, before sunburn) and supplementation during winter is practical. Your GP will advise based on your level, skin type, latitude, and personal cancer risk. The Cancer Council provides a UV widget to help balance vitamin D and skin protection.

Disclaimer:This information is educational only and not medical advice. Results should be interpreted by your health practitioner in the context of your symptoms and health history. Treatment decisions should be made with your doctor or specialist.