S -D-25 KL 1220

Vitamin D is a lipid-soluble vitamin. It has a hormone-like effect in calcium and phosphorus metabolism, enhancing their absorption. In addition, vitamin D affects our health in many other ways, and its role in preventing illnesses has been studied extensively. The body stores vitamin D in the calcidiol form (S-D-25). Vitamin D is converted to the active calcitriol form in the body (S-D-1.25).


Monitoring of vitamin D treatment. At-risk group includes: elderly people, pregnant women, children under 2 years of age who do not receive vitamin D supplements, people with limited exposure to sunlight (e.g. inpatients).


Blood sample. Normal eating and drinking is allowed.

No vitamin D supplements 12 hours before sampling.


1.5 mL (minimum 1 mL) of serum or Li-heparin plasma.

Storage and delivery

Delivery at room temperature on the sampling day if it arrives the next day (Mon-Fri). Can be stored refrigerated over the weekend, ship at room temperature.


Liquid chromatography (HPLC).

Turnaround time

5 – 10 weekdays

Reference ranges

Below 25 nmol/L: serious deficiency
Below 50 nmol/L: deficiency
50 – 75 nmol/L: generally regarded as sufficient concentration
75 – 130 nmol/L: recommended concentration

Toxic concentration over 375 nmol/L.