New performance specifications for Vitamin D analysis

A University of Dundee expert and his colleagues have received a prestigious international honour after creating a new model to assess the performance of analyses of Vitamin D in blood. 

Professor Callum G Fraser and the group have received the European Federation of Clinical Chemistry and Laboratory Medicine Award for Excellence in Performance Specifications Research. 

Along with international collaborators, Professor Fraser developed updated analytical performance specifications (APS) which could facilitate the assessment of vitamin D analytical methods. The new model could have a positive impact on the analysis of samples from patients with vitamin D deficiency.  

Vitamin D is produced by the body in response to skin being exposed to sunlight. It is also present in foods such as fish, fish liver oils and egg yolks. Accurate monitoring of vitamin D levels for diagnosis and treatment is key to improving the lives of patients and delivering appropriate and efficient treatment.   

Blood tests are used to determine an individual’s vitamin D status using APS to try to ensure good methodology however, the methods currently used are assessed using an APS developed over a decade ago.  

The new model was developed by Professor Fraser and colleagues using data on vitamin D on samples taken by six European laboratories that recruited 91 healthy participants, with samples taken over 10 weeks.  After examining the biological variation of vitamin D levels, the team were able to develop and propose a new approach to APS.  

Professor Fraser said, “We considered that current analytical performance specifications (APS) for vitamin D measurements required updating.  The favoured strategy to set APS is based upon estimates of inherent biological variation.  We initially set out to update the estimates of Biological Variation using modern analytical techniques and calculation strategies.   

“However, we showed that individuals are not in steady state, a prerequisite for this approach. Therefore, a new model was needed. We developed this using data on the natural rise in vitamin D in individuals in Spring in Europe, taking the current criteria for deciding whether a supplementation of an individual was successful into account.  

“We demonstrated two very important points. The first is that the traditional approach to the generation and application of data on biological variation was not applicable to vitamin D measurements, especially in the setting of APS.  

“Indeed, there is no steady state in vitamin D over time and any model based on random variation around homeostatic setting points is inappropriate. The second important point is that we proposed a new model to set APS based on the physiological variation of vitamin D over time and the interpretation of vitamin D levels in clinical practice.  

“If our model became widely accepted in due course, measurements of vitamin D should improve, benefitting a wide range of patients in whom vitamin D levels are vital for good care.  Moreover, our model might be applied to other investigations done in laboratory medicine for which there are temporal trends rather than random variation over time.” 

This unique study has resulted in a position statement from the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) Committee on Bone Metabolism, which provided support that the currently used APS could evolve to use this new model. 

The EFLM Award is given to the best published paper, as judged by an independent panel of experts, which demonstrates an important and novel contribution to the theory or practical application of performance specifications. The Award, which is €5000, is being donated to the Missione Kidane Mehret Adwa, Tigray, Ethiopia.  

The paper can be found here.