Scheme Information Sheets

UK NEQAS for Vitamin D

Scheme Particulars Indicative Details
Accreditation body UKAS
ISO/IEC Accreditation status ISO/IEC 17043:2010
UKAS Accredited Proficiency Testing Provider No 7860
Objective of Scheme Provides EQA coverage and analytical assessment using endogenous material for Vitamin D. The Scheme covers the analytical working range but does focus at the clinically important lower concentrations.

The Target Value is the Mass Spectrometry method mean, but this is validated annually by analyses of a number of pools by a reference method at CDC in Atlanta
Pre-, Analytical, Post- status Analytical/Post
Number of distributions per year (nominal) 11
Specimens per distribution 3
Number of Specimens per annum 33
Frequency of distribution Monthly
Scoring system ABC
Material distributed Pooled, liquid human serum with or without exogenous added analyte
Programme Director(s) / Organiser(s) Rachel Marrington
Criteria for participation All, but overseas by courier
Nominal sample volume (mL) 0.4
Sample presentation TACs All analytes in the same tube
Data in Chemistry on-line Dashboard Yes
Analyte Approx Range Default Units Target Value B Score Limit (%) C Score Limit (%)
25-OH Vitamin D2 0 – 250 nmol/L OGLTM 20.0 25.0
25-OH Vitamin D3 0 – 250 nmol/L OGLTM 20.0 25.0
Total 25-OH Vitamin D 0 – 250 nmol/L OGLTM 20.0 25.0
Vit D Interpretation ~ D, I, A or T ~ ~ ~
Abbreviation Expansion
ALTM All Laboratory Trimmed Mean
GLTM Group Laboratory Trimmed Mean – which is the Method Principle Mean
MLTM Method Laboratory Trimmed Mean – usually a manufacturer system / analyser mean
XALTM An external value that may be from a Reference Method System
OGLTM A Method Principle Mean used as the target for all laboratories
OMLTM A specific Method Mean used as a target for all laboratories
MED Median

Last Updated: