The Clinical Laboratory Improvement Amendments (CLIA) represent a set of federal regulations established to govern all laboratory testing on human specimens in the United States. The purpose of this regulatory framework is to ensure that test results used for diagnosis, prevention, or treatment are consistently accurate and reliable, regardless of where the testing is performed. CLIA categorizes laboratory tests based on their complexity, ranging from high to moderate to the least complex category known as waived tests. Waived tests are defined as those procedures so simple and straightforward that they carry a low risk of producing an incorrect result when performed properly.
Criteria for CLIA Waived Status
The determination of which tests receive waived status is overseen primarily by the Food and Drug Administration (FDA). To be categorized as waived, a test system must meet strict criteria, exempting it from most CLIA requirements. A device is eligible if its methodologies are simple and accurate enough to make the likelihood of an erroneous result by the user negligible. The FDA evaluates the test to ensure it poses no reasonable risk of harm to the patient if performed incorrectly. Tests already cleared for over-the-counter or home use are automatically categorized as waived because of their inherent simplicity.
Manufacturers of devices initially categorized as moderate complexity may also submit a request, known as a CLIA Waiver by Application, to the FDA to reclassify the test. This application must include scientific data demonstrating that the test system meets the statutory criteria for simplicity and negligible error risk. The focus is entirely on the design of the test method itself, ensuring that personnel without specialized laboratory training can execute the procedure and interpret the results correctly.
Common Categories of Waived Tests
Waived tests are widely used in point-of-care settings like physician offices, pharmacies, and urgent care centers. They provide rapid results with minimal technical complexity and fall into several broad categories, offering immediate diagnostic information.
In clinical chemistry, common waived tests include systems for monitoring blood glucose. Certain tests for cholesterol and high-density lipoprotein (HDL) are also available as waived systems, allowing for immediate lipid screening. These tests typically use a small sample of whole blood and provide a numerical result on a simple digital screen.
Urinalysis is a major category for waived testing, primarily through the use of reagent strips, or dipsticks, for chemical analysis. These dipsticks can simultaneously screen for multiple analytes, including pH, protein, glucose, ketones, and blood, by observing color changes on the strip. Similarly, some basic hematology procedures, like the spun microhematocrit, which determines the volume percentage of red blood cells, are classified as waived.
Immunology and microbiology also feature numerous rapid waived tests that rely on simple immunoassays. Examples include:
- Urine-based pregnancy tests, which detect the presence of the hormone human chorionic gonadotropin (hCG).
- Rapid diagnostic tests for infectious diseases, such as rapid strep throat screens and influenza tests.
- Fecal occult blood tests (FOBT), which screen for hidden blood in stool samples.
Operational Requirements for Performing Waived Tests
Any facility that intends to perform a CLIA-waived test must first obtain a Certificate of Waiver (COW) from the Centers for Medicare & Medicaid Services (CMS). This involves submitting an application to the appropriate state agency and paying the required certificate renewal fee on a biennial basis to maintain status.
The most fundamental operational requirement is absolute adherence to the manufacturer’s instructions for the specific waived test system. Any deviation from the established procedure, such as using an unapproved specimen type, voids the waived status of the test. Such an unauthorized modification reclassifies the test as high complexity. This subjects the facility to significantly more stringent CLIA regulations, including proficiency testing and quality control requirements.
Although CLIA does not mandate specific personnel qualifications or routine inspections for waived test sites, facilities must ensure staff are properly trained to follow the manufacturer’s instructions. Facilities are expected to implement basic quality assurance practices, such as verifying reagent expiration dates and ensuring proper storage conditions. The COW allows the facility to perform only those tests that have been designated as waived.