Question regarding a reference or a guide that specifies the practice of sending same sample to multiple labs.
Testing a sample for Protein % (higher protein is desirable)
Seller sends the same sample to 2 different labs for Protein testing on a routine basis. Depending on the situation, and without knowing who the potential customer is going to be, both COAs are kept and only one is presented when the customer is determined.
Background: some customers (based on Quality Agreements) specifically requests COAs be tested with their approved lab. But they would want to know the Protein % before committing to the purchase. The sample for micro & heavy metals etc. is then tested based on the customer's selected lab in order to have QA release on seller's side.
What are your thoughts on this practice?
Is there something in Good Laboratory Practices, ISO 17025, or other standards and guidelines that says this is not a good practice?
If this practice is to be continued as a business decision, is this justified based on Quality Agreements?
Sorry but I don't entirely understand the OP.
What is yr objection to the buyer's requirement ? Not trust the lab ? Not trust the sample ?
TBH, since you, the seller, are presumably paying for the analysis, IMEX the choice of Lab should be negotiable if you are not happy with the buyer's suggestion.
IMEX, the seller/buyer typically agree on a minimum % protein for a lot, (usually a sample-based average). As long as the lab. result complies with minimum specification, the remuneration is independent of the specific value.
(Furthermore, IMEX buyers usually sample/test the Lot quality on reception. Failure to meet contracted minimum > claim).
IMEX no two labs will give an identical numerical result on a "same" sample. ( = sampling/analytical error)
Arguments can occur when one lab gives a result just above a minimum specification and another gives a result just below, ie the true value is likely close to the contracted requirement. This IMEX can lead to a third referee analysis.
Or are you being paid depending on the absolute protein level ?. This can involve determining whether a particular lab procedure has bias (+ or, particularly from sellers POV, - ).
@ ABFC - thks compliment but memory sadly fails in this instance. However the event(s) you refer could certainly occur hence this rather cryptic phrase which typically, somewhere, appears on most, independent, 3rd party Lab reports - "The results stated apply only to the sample as received".