Are there US laboratories which are accredited for European testing?
No. Laboratories can be accredited only within the EU. The EU system does not allow for third party certifications, accreditation or approval unless the organization is operating under a mutual recognition agreement negotiated between the EU and government authorities of the third country. The US cannot become a member of the EU, there is a Mutual Recognition Agreements that has been initialed but not executed. The US Department of Commerce is engaged in ongoing negotiations.
