Scheme Information Sheets

UK NEQAS for Vitamin K

KEQAS Standard Reference Material-2 (SRM-2) is a serum reference material for validation of methods measuring vitamin K1 (phylloquinone). It is available to purchase from the Nutristasis Unit, Synnovis. Please contact Ella.freke@gstt.nhs.uk or Nathan.timbrell@gstt.nhs.uk for further information.

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 for Vitamin K1 and a number of pilot analytes (pilot analytes not accredited to ISO/IEC 17043). The Scheme is operated quarterly and the specimens are dispatched once per year, therefore the participant is required to store specimens in their freezer (-20 degrees or less) until the time of analysis
Pre-, Analytical, Post- status Analytical
Number of distributions per year (nominal) 4
Specimens per distribution 3 (2 for pilot analytes)
Number of Specimens per annum 12
Frequency of distribution Quarterly
Scoring system ABC
Material distributed Single or Pooled, liquid 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) 1.8
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 (%)
Vitamin K1 0 – 8 ug/L ALTM 40.0 60.0
K1 (Pilot) 0 – 8 ug/L ALTM ~ ~
K1 2,3-epoxide (Pilot) 0 – 20 ug/L ALTM ~ ~
MK-4 (Pilot) 0 – 20 ug/L ALTM ~ ~
MK-7 (Pilot) 0 – 20 ug/L ALTM ~ ~

Analyte not yet accredited to ISO/IEC 17043:2010

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

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