MAINTENANCE OF THE QUALITY STANDARD
The technical competence, impartiality and reliability of the analytical data are attested by the constant participation in Proficiency Testing performed for different matrices and analytes. The evaluation of laboratory testing performance by means of interlaboratory comparisions. (International Standard ISO/IEC 17043:2010: Conformity assessment, general requirements for proficiency testing).
Planned control of analytical activities performed by the laboratory
Selected Proficiency Testing Providers:
- FAPAS (UK)
- LGC (UK) for microbiology (UK)
- Others: (COI – olive oil), BIPEA (Filth test, nutritional analysis, contaminants), QS (Pesticides and Dioxins -PCBs)
- GAFTA (Analysis in Grain and Feed)
- FOSFA (UK): Ptest related to specific analyses on oil and oil seeds
- Health Ministry Norway: Ptest DIOXIN e PCB
- PROOF-ACS for contaminants
- DRRR for total migration analysis, specific, and MOSH -MOAH
- DLA (Germany)
Statistical evaluation of results
Generally, the laboratory’s performance assessment is expressed in the standardised form of z-score. Z-score that expresses, from the statistican point of view, the divergence of the laboratoty’s reported result (X) from the most probable result (µ), also called assigned value.
σ = standard deviation
As a general rule, a z-score within the range |z| <=2 is considered satisfactory. In fact, the terminology “satisfactory” for z-scores |z| <=2 and “unsatisfactory” for |z| >2, is widely used in proficiency testing.
To request the last P-Tests results, please contact Quality Assurance.