If tests come with accepted tolerance ranges do you still do measurement uncertainty? Also if you use international standards which are validated already do you still need to validate the method in the lab?
"If tests come with accepted tolerance ranges do you still do measurement uncertainty?
I assume, based on you next question you are referring to a Standard test method. ISO 17025 states in clause 7.6.3, note 1 that if a laboratory follows a well-recognized test method that specifies limits to the values of the major sources of measurement uncertainty and specifies the form of presentation of the calculated results; and the laboratory follows reporting instructions, the laboratory is considered to have satisfied requirements of clause 7.6.3 to evaluate measurement uncertainty. So if this is the case, you will not need to perform MU as a testing Laboratory. Note that in all cases however you need to assess the risk of misrepresenting the results to clients. Furthermore calibration laboratories must always report the MU on a calibration certificate.
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Also if you use international standards which are validated already do you still need to validate the method in the lab?"
You must meet the requirements of ISO 17025:2017 Clause 7.2, meaning if it is standard method your extent of validation is to verify that your laboratory can meet the performance criteria of the standard test with you conditions of venue, equipment and personnel. This could be, for example the required sensitivity, specificity, or other parameters stated.