|Limits for the interlaboratory comparison test evaluation|
With beginning of the 14th Needle and Leaf Interlaboratory Test a laboratory will pass the test if a LOQ is reported only if:
- the LOQ is equal or lower than the max. tolerable LOQ (see table)
- the reported LOQ is within the tolerable limits (lower limit) for the parameter.
If the outlier free mean (or the median) for the sample is lower than the lowest evaluated result, this sample is not used in the qualification report. This procedure is needed because:
concentration is too low to detect it accurate from the participating
laboratories (this influence the calculation of the outlier free mean)
- the result give no practical relevant information of the nutrient status (Cu: deficency) or of the pollution impact situation (Cd, Cu, Pb : not polluted) of real monitoring samples.
Up from the 19th Needle/Leaf Interlaboaratory Test preliminary limits for some heavy metals were used for the evaluation: