It can realistically take from six to twelve months for the accreditation process to be completed. i.e from application to accreditation.
Once you have applied for accreditation with an accreditation body (AB) and submitted all the required documents they will do a document review. This could take a few months depending on how busy the AB is. Depending on the extent of laboratory “readiness”(if documents are available and requirements met) it can be another month or more to close any gaps. It may then take another month or two before the initial assessment (audit) of your processes and documents. Finally the laboratory may need another month or more to close any non-conformances, before accreditation is achieved.