Laboratory methods of measuring vitamin D – quo vadit?

Abstract:

Laboratories all over the world are registering continuous increase in the number of requests for vitamin D measurement, which has been particularly pronounced during the current COVID-19 pandemic. So far, correlation between the serum vitamin D levels and various diseases and conditions not associated with calcium absorption and bone metabolism has only been speculative. Immunochemistry methods for vitamin D measurement are readily available and easy to apply in all types of medical biochemistry laboratories, but their drawbacks are insufficient specificity and occasionally particularly low agreement between them. Tandem mass spectrometry is a novel, more frequently used laboratory alternative option, yet it requires sophisticated analytical equipment and specially trained staff. Due to better specificity, the values for vitamin D obtained by using this method are commonly lower than those measured by immunochemistry methods. Longitudinal follow-up of vitamin D levels should therefore always be carried out using the same laboratory method, while indications for measurement should been defined by adequate guidelines.

Key words:
laboratory immunochemistry methods; tandem mass spectrometry; vitamin D