Vitamin D plays a vital role in the body. Unfortunately few foods naturally contain Vitamin D, and only in very low amounts. Further, it is a challenge to acquire the required vitamin D levels safely through sunlight.
Kits have a 6 month expiry date.
After sample collection, samples are stable for at least 2 weeks. However it is good practice to send the sample back to the lab on the same day that you collect your blood sample (preferably on a Monday to Thursday during working days, so that the sample can be processed quickly before the weekend).