LAB is abbreviation established to adress specifically authorized organization for purpose of language proficiency assessments of flight crew and air traffic controllers.
LAB stands for Language Testing Body and the name was established in Ec 1178/2011, FCL.055 and respective acceptable means of compliance with FCL.055. Language Testing Body or LAB has its own structore and management systems simpler, but very similar to ATO - Approved training organization structure.
Language assessment body must be in possession of holding own Operation manual and Quality management system. Language assessment body (LAB) is certified by National Aviation Authority.
LAB or Language testing body was replaced with LTB or Language Testing Body by Amendment 9 of Acceptable means of compliance to Part FCL.
In other than EASA region, the equivalent of Language Testing Body is called TSP or Testing Service Provider.