Collaborative Testing Services, Inc.
P.O. Box 650820, Sterling, VA, USA 20165-0820  1-571-434-1925
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Quality buzzwords may come and go, but one thing has remained the same since 1971: CTS' unwavering commitment to assisting laboratories in meeting their quality assurance objectives. Find out how our interlaboratory and proficiency tests can help you achieve better measurements, better control, and better laboratory performance. We offer testing programs for:

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The first and still the largest forensic proficiency test provider, CTS has set the benchmark for forensic tests since 1978. Organizations around the world turn to CTS each year to meet their proficiency testing needs. Check out our tests offered across 10 disciplines:

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You are a click away from the most comprehensive client portal offered by a proficiency test provider. The CTS Customer Portal opens the door to...

Testing Instructions
Data Management
(including data entry, revisions, history)
Guides to Interpreting Reports
Order History
Test Delivery
(for digital download tests)

CTS' COVID-19 Response

In light of the rapidly-evolving COVID-19 situation worldwide, CTS is working to ensure continuing operation of our proficiency testing programs in support of our participating laboratories, promote the health and well-being of our employee-owners, and protect the communities where we live and work.

Interlaboratory Testing Program Status:

We understand the reliance that our customers place on our testing programs to satisfy quality assurance objectives and meet regulatory requirements and appreciate the trust placed in our services. We remain steadfastly focused on ensuring that trust is well placed.

As of April 25th, our testing programs have experienced minimal interruptions. To assist clients, many data due dates have been extended. All affected clients have been notified of these changes via email, and current Test Status information is always available to our Primary Contacts and their designees on the

Moving forward, should COVID-19 cause a delay we will notify all impacted customers immediately via email and the updated Test Status page on the CTS-Portal. We will continually monitor local, situational updates and maintain contact with vital suppliers to keep abreast of the evolving impacts of COVID-19. In this way, we will provide participants with as much forewarning as possible if an impact is anticipated.

Should the local situation prevent your laboratory from receiving a testing package or if an extension to the data due date for a particular test or cycle is required as a result of COVID-19, please contact CTS. We will attempt to service each need to the maximum extent possible, with regard to your local situation. As always, our Coordinators and Program Analysts stand ready to reply to your questions and your requests for data submittal extensions. You may also contact our Subscriber Services team at should you not have direct contact information for your testing. You may call us at +1-571-434-1925, but due to reduced staffing email contact may be more efficient.

CTS Office Staffing Status:

CTS' employee-owners are our greatest resource, and we will always evaluate how best to protect their health and wellness. We proactively monitor our local situation and make adjustments to our operations to safe guard this resource and minimize disruption. Currently, we have closed our office to the public and for non-essential work. However, we intend to work remotely to maintain an open for business as usual presence and we intend to fulfill all our commitments to clients. With the majority of our staff working from home, we do ask that requests for assistance be sent via email directly to our Coordinators and Program Analysts or to our general The minimal staff who are in the office will maintain the daily hygiene routine, and will attempt to answer phone calls.

We thank you for your kind understanding and cooperation.