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2021 Proficiency Test (PT) on Preservatives in Skin Care started


The letter of instructions can be downloaded here as a pdf document. To download a document, please click the right mouse button and choose the "save as" option.


 Please download the instructions for the PT iis21H07 here: the letter of instructions and the report form here



Summary of this proficiency test:


On 3 November the proficiency test on Preservatives in Skin Care started with 18 participants from 14 different countries. On that date, the samples were dispatched to the laboratories.

Please confirm sample receipt as soon as you have received and checked the contents of the sample package via Please enter the date of receipt and press the "save date" button.


The samples can be analyzed on: CMIT (5-Chloro-2-methyl-4-isothiazolin-3-one), MIT (2-Methyl-4-isothiazolin-3-one) . 


The deadline for reporting results is set on 10 December  2021. A laboratory that reports test results after the deadline will definitely not get direct feedback in case any of its results are suspect! So be in good time to get the most out of this proficiency test.

The test results should be reported via our internet based results reporting platform A login and a password can be requested via email to





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