Contact CLSI: Get in Touch with Us Today

We’d be happy to speak with you more about our products, programs, membership, and mission.

Mailing Address

Clinical and Laboratory Standards Institute
PO Box 334
Malvern, PA 19355

Office Address

Global Headquarters
Clinical and Laboratory Standards Institute
1055 Westlakes Drive, Suite 300
Berwyn, PA 19312

Please send payments to:

Clinical and Laboratory Standards Institute
PO Box 645766
PITTSBURGH, PA 15264-5255

Please send overnight courier payments to:

PNC Bank C/O Clinical and Laboratory Standards Institute
Lockbox Number 645766
500 1ST AVE
PITTSBURGH, PA 15219

Phone Numbers

Phone: +1.610.688.0100
Fax: +1.610.688.0700
Toll Free (US): 877.447.1888

Customer Service phone hours
8:30 AM–5:00 PM Eastern (US) Time

E-mail Us

Membership Inquiries: [email protected]

Customer Service, Orders, and General Questions: [email protected]

Technical Questions

If you have technical questions regarding the content of CLSI standards and guidelines, please e-mail [email protected].