Vitamin D test in Zurich — when to get tested and what the values mean

Dr. Charalampos Romanos · 22 December 2025 · 5 min read

Over half the population in central Europe has insufficient vitamin D levels — in winter months, the figure is even higher. But when is a test actually useful and what do the values mean?

When a vitamin D test makes sense

Not everyone needs a measurement. Testing is useful for fatigue, muscle weakness, bone or joint pain, frequent infections, winter mood changes, or risk factors such as low sun exposure, dark skin, or a vegan diet. As part of a health check, we measure vitamin D routinely.

What the values mean

We measure 25-OH vitamin D in blood. Below 30 nmol/L is deficient, 30–50 nmol/L is insufficient, 50–125 nmol/L is optimal. Values above 250 nmol/L can be toxic. In my practice, the majority of winter tests come back below 50 nmol/L.

Supplementation: how much and how long?

Dosing depends on the baseline value. For significant deficiency, we often start with a loading dose and then move to maintenance. Self-supplementation without testing is possible but not ideal — excessive doses can cause harm. More in our article on vitamin D deficiency.

Cost and insurance

Vitamin D measurement is covered by basic insurance when medically indicated. For pure screening without symptoms, it can be done as a self-pay test — we inform you transparently.