FDA Classification and Requirements for Approval
The FDA classifies medical devices, including laboratory tests, based on the level of control needed to assure that the device is safe and effective. Devices that support or sustain human life, present a potential or unreasonable risk of illness, or can greatly prevent human health from being impaired fall into FDA's most stringent category, Class III, and must demonstrate reasonable assurance of safety and effectiveness before being approved for marketing in the US. These are tests that are subject to the highest standards of proof of their safety and effectiveness and may require the most time and resources to gain approval. Examples of Class III devices in the laboratory are the tests used to diagnose cancer and those used to detect antibodies for the Hepatitis C virus, which, if untreated, can lead to chronic liver disease.
By comparison, Class I devices pose little risk to human life and are generally not as complicated, so they are exempt from FDA review. A simple blood test to determine uric acid concentrations in serum uses a method that is well understood and has been in use for many years. It is relatively straightforward to monitor the quality of test results and to ensure that the test is performing to specifications. In addition, the test, which falls under the Class I category, provides supportive evidence to a doctor's preliminary diagnosis of gout, a nonfatal and generally treatable disorder.
Besides assessing the potential risk to the patient, the other factor used to classify tests is the FDA's familiarity with the test process itself and the medical devices and equipment used to produce the result. Under the 1976 Safe Medical Device Act that established the FDA's regulation of medical devices and tests, manufacturers are required to notify the agency of their intent to market a new product. The FDA permits most Class I and II medical devices to be marketed after the manufacturer can demonstrate that the device is "substantially equivalent" or as safe and effective as a similar device already on the market.
Devices or tests that have a new use or that pose new issues of safety and effectiveness generally require submission of a pre-market approval (PMA) application with valid findings from human clinical trials that demonstrate that the device is clinically effective for its intended use. In addition to reviewing and approving the clinical data from the company-sponsored trials, FDA also confirms that the device will be manufactured in conformance to good manufacturing practices.
As an example of a PMA, in December 1998, the FDA granted approval to Vysis, Inc., a genomic disease management subsidiary of Abbott Laboratories, Abbott Park, IL, to market a testing kit that can detect amplification of the Her-2/neu gene from human breast cancer tissue specimens. Detection of multiple copies of this gene in patients is important since these patients tend to experience rapid tumor growth, resistance to therapy, and decreased survival rates. Detection of the gene can allow doctors and patients to choose the most beneficial form of treatment, according to the company.
In addition to FDA approval, all commercial tests must be evaluated by individual laboratories before they are put into use. A lab must demonstrate that it can perform the test with the same accuracy and precision as specified by the manufacturer of the test. And commercial tests, once they have been put into practice, must be evaluated on a regular basis with in-house quality assurance programs to ensure that performance of these tests continue to meet specifications. As is true for any laboratory test, on-going assessments of commercial tests are regulated by CLIA. This topic is discussed further in the article Lab Oversight: A Building Block of Trust.
Read more on FDA Test Classifications
To learn more about the FDA's clearance and approval process for laboratory tests, visit the FDA webpage on Medical Devices.