Clinical laboratory test systems are assigned a moderate or high complexity category on the basis of seven criteria given in the CLIA regulations. For commercially available FDA-cleared or approved tests, the test complexity is determined by the FDA during the pre-market approval process. For tests developed by the laboratory or that have been modified from the approved manufacturer’s instructions, the complexity category defaults to high complexity per the CLIA regulations. See 42 CFR 493.17.
As defined by CLIA, waived tests are simple tests with a low risk for an incorrect result. They include certain tests listed in the CLIA regulations, tests cleared by the FDA for home use, and tests approved for waiver by the FDA using the CLIA criteria. Sites performing only waived testing must have a CLIA certificate and follow the manufacturer’s instructions; other CLIA requirements do not apply to these sites.
Nonwaived testing is the term used to refer collectively to moderate and high complexity testing. Laboratories or sites that perform these tests need to have a CLIA certificate, be inspected, and must meet the CLIA quality standards described in 42 CFR Subparts H, J, K and M.
PPM procedures are certain moderate complexity microscopy tests commonly performed by health care providers during patient office visits. The PPM subcategory includes a limited set of microscopic evaluations listed in the CLIA regulations that are performed on samples such as urine, skin scrapings and excretions. CLIA offers a PPM certification option for this limited set of moderate complexity tests to accommodate the unique needs of health care providers in clinical settings. Only certain types of providers qualify as testing personnel for PPM tests under a PPM certificate, including physicians, dentists and midlevel practitioners. See 42 CFR 493.19. Also, CMS’ List of PPMP Tests (including CPT/HCPCS codes).
Exceptions to the CLIA regulations exist for certain testing, including employment related drug testing by SAMSHA certified laboratories, testing performed for forensic purposes (criminal investigations), and research or surveillance testing performed on human specimens in which patient specific results are not reported (if the results are not used for diagnosis or treatment decisions). For more information, please refer to CLIA at 42 CFR 493.3(b).
For moderate and high complexity tests, the FDA evaluates each new commercial test system during the premarket approval process by scoring seven criteria as described in the CLIA regulations.
The final score is used to determine whether the test system is classified as moderate or high complexity. See 42 CFR 493.17. For more details, please also see the FDA’s webpage on the CLIA Categorization Criteria and CMS’ webpage on Categorization of Tests.
For waived tests, the FDA may grant a waiver to: 1) any test listed in the regulation, 2) any test system for which the manufacturer or producer applies for waiver if that test meets the statutory criteria and the manufacturer provides scientifically valid data verifying that the waiver criteria have been met, and 3) test systems cleared by the FDA for home use. Please see the FDA’s webpage on CLIA Waivers.
Clinical laboratories or other testing sites need to know whether a test system is waived, moderate or high complexity for each test on their menu as it determines the applicable CLIA requirements. In general, the more complicated the test, the more stringent the requirements under CLIA. Laboratories or sites that perform only waived tests need only follow the manufacturer’s instructions for those tests to meet CLIA requirements. Nonwaived testing is subject to inspection and must meet the CLIA quality system standards, such as those for proficiency testing, quality control, and personnel requirements. The standards for moderate and high complexity testing differ only in the personnel requirements. The categories of tests a laboratory offers is also a factor in determining the appropriate CLIA certificate for the laboratory. For a general overview of CLIA certificate types, see CMS’ Clinical Laboratory Improvement Amendments (CLIA) Brochure.