Question 1

How to prepare for a vitamin D test?

Accepted Answer

Donate blood in the morning on an empty stomach. Avoid taking vitamin supplements 24 hours before your test.

Question 2

Is it possible to make up for the deficiency with sunlight alone?

Accepted Answer

In northern latitudes and in winter there is not enough sunlight; correction with nutrition or supplements is required.

Question 3

What foods are rich in vitamin D?

Accepted Answer

Fatty fish (salmon, herring), egg yolks, liver, fortified dairy products.

Question 4

What are the dangers of excess vitamin D?

Accepted Answer

Hypervitaminosis leads to tissue calcification, nausea, and kidney dysfunction. Requires medical supervision.

Question 5

Which form of vitamin D is best absorbed?

Accepted Answer

D3 (cholecalciferol) is more effective at increasing 25-OH-D levels than D2 (ergocalciferol).

Group	Minimum	Maximum	Interpretation
Optimal	40 ng/mL	60 ng/mL	Optimal
Sufficient	30 ng/mL	100 ng/mL	Reference range
Deficiency	—	20 ng/mL	Needs correction

Vitamin D (25-OH)

Reference ranges