When they are processed in the USA they are not only processed according to different standards, but also in terms of comparability, not reproducibility. Reproducibility and comparability are often, depending on the value measured, dependent on the concentration or, in the case of element determination, also on the element in question. The results are more scattered when analysing comparability than for reproducibility and again at low concentrations more than for high concentrations. In the DIN this is illustrated for the element iron as an example: At a concentration in the range of 1-10 mg/kg fluctuations in the results of 15% from the mean value for reproducibility (in the same laboratory) and deviations of 60% from the mean value for comparability (different laboratories) are tolerable. At higher concentrations, from 10-1,000 mg/kg, the results for reproducibility may only vary by 5% and those for comparability by 25%. The numbers show that with a mean value of 50 mg/kg, values of 44 mg/kg and 56 mg/kg are considered to be valid, if the results from two different laboratories are compared. Conclusion: If a particular sample is analysed in different laboratories, it is a question of a comparable, but not reproducible process. Also comparable values determined according to a standard can in part differ considerably from each other. The OELCHECK laboratory in Germany has markedly improved the tolerance range for comparability, because in both locations analysis is carried out with identical standards, equipment types and calibration standards. In that way the values are of the same standard as they would be if they were within the narrow range for reproducibility. By the way: In case of doubts regarding a diagnosis by an external laboratory you can, for a small fee, have the diagnosis compiled by OELCHECK tribologists.