Four sets of weights (PTA 1, PTA 2, PTA 3 and PTA 4) were distributed amongst the 19 participating laboratories. Each set consisted of two aluminium weights, one nominally 5 mg, and the other nominally 20 mg.

All laboratories except one returned results for inclusion in the report.


The Final Report is issued on the PTA website, and can be accessed by selecting Programs, then selecting Reports 2018. The report number is 1073.

PTA programs have been used by laboratories to satisfy accreditation requirements, educate staff, verify methods and procedures, enhance accuracy, demonstrate competence, assess performance, compare with peers, monitor analysis, identify problems and improve testing.

Registration for participation in the Gravimetric Round 6 Proficiency Testing Program will be open in January 2019.
For more information about the above program, please contact
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