Scheme Information Sheets
UK NEQAS for Vitamin Assays
| Scheme Particulars | Indicative Details |
|---|---|
| Accreditation body | UKAS |
| ISO/IEC Accreditation status | ISO/IEC 17043:2023 |
| UKAS Accredited Proficiency Testing Provider No | 7860 |
| Objective of Scheme | Provides EQA coverage for Vitamin assays used in the management of vitamin and nutrition status. This Scheme provides both manipulated and endogenous samples that cover both the normal and pathological concentration ranges for Vitamin A and E and Beta carotene. This dedicated scheme also offers the measurment of other caroteniods such as Alpha carotene, Lyopene, Beta cryptoxanthin, Lutein and Zeaxanthin |
| Pre-, Analytical, Post- status | Analytical |
| 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) | Finlay MacKenzie |
| Criteria for participation | All, but overseas by courier |
| Nominal sample volume (mL) | 1.2 |
| 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 (%) |
|---|---|---|---|---|---|
| Alpha carotene | 0 – 0.8 | µmol/L | ALTM | 30.0 | 40.0 |
| Beta carotene | 0 – 4 | µmol/L | ALTM | 20.0 | 25.0 |
| Beta cryptoxanthin | 0 – 0.8 | µmol/L | ALTM | 20.0 | 25.0 |
| Lutein + Zeaxanthin | 0 – 0.8 | µmol/L | ALTM | 20.0 | 25.0 |
| Lycopene | 0 – 1.2 | µmol/L | ALTM | 30.0 | 40.0 |
| Vitamin A | 0.5 – 3.5 | µmol/L | ALTM | 15.0 | 20.0 |
| Vitamin E | 5 – 60 | µmol/L | ALTM | 15.0 | 20.0 |
| Zeaxanthin | 0 – 0.4 | µmol/L | ALTM | 20.0 | 25.0 |
| 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 |
