Medical Test Sites (MTS)

Welcome to the Medical Test Site Program webpage. Here you'll find information regarding the licensing of Medical Test Sites — sites that perform clinical laboratory testing for the purpose of diagnosis and treatment. 

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Proficiency Testing 

Laboratory Developed Tests (LDTs) 

  • FDA has proposed to gradually end their enforcement discretion approach in stages over a 4-year phase out period and expects IVDs offered as LDTs to meet applicable FDA approval requirements. Review the proposed rule: Federal Register :: Medical Devices; Laboratory Developed Tests


To ensure that the public receives accurate and reliable clinical laboratory services and test results by monitoring and evaluating medical test sites for compliance with minimum standards of quality assurance for clinical laboratory testing.

History and Background

The federal Clinical Laboratory Improvement Amendments (CLIA), which requires certification of all sites performing clinical laboratory testing, was passed in 1988. Prior to 1988, the only laboratories that were regulated were those that did interstate testing, or independent laboratories and hospitals that wanted Medicare reimbursement. CLIA changed the picture dramatically by including all sites where testing was being performed, such as doctor's offices, clinics, health departments, etc.

The legislature passed the Medical Test Site (MTS) Licensure law (chapter 70.42 RCW) in May 1989 to allow the state to regulate clinical laboratory testing. The rules to implement the law (chapter 246-338 WAC) were adopted in October 1990.

In September 1992 the federal regulations to implement CLIA became effective. CLIA allowed equivalent state programs to apply for exemption from Federal regulation. Washington State applied for exemption in October 1992. In October 1993, Washington became the first state to have its clinical laboratory licensure program judged by the Federal Health and Human Services Centers for Medicare and Medicaid Services (CMS) as equivalent to CLIA and was granted an exemption. This exemption from CLIA retains the regulatory activity at the state level, rather than federal, where it is more accessible and responsive to local needs.

In 1996, the Joint Commission granted deemed status to the Washington State MTS program. This allows laboratories in Joint Commission accredited facilities to be inspected under the MTS program.

Contact us File a Complaint Verify an existing Medical Test Site License