Introduction Development Approval Practice Lab Developed Assays Classification Coverage Sources

SIDEBAR 2
FDA Classifications of Medical Devices

Medical devices, which perform a diagnostic test in a clinical laboratory or health care setting, fall into one of three categories for FDA clearance and approval to market. Devices are categorized by intended use and by risk to determine the degree of review that is necessary to ensure that safety and effectiveness are met. 

• Class I devices present minimal potential for harm to the user and are often simpler in design than either Class II or Class III devices. They include items such as enema kits and elastic bandages, common laboratory tests such as cholesterol, iron, and pregnancy tests, and most laboratory instrumentation. Class I devices are those that can be monitored by general controls. Some of the general controls that the FDA uses are: 1) the device must be registered with the FDA; 2) devices must be manufactured using Good Manufacturing Practices; 3) the labeling of the device must at least tell the user the product name, intended use, type of procedure it is, and - if it is an instrument - installation, operating, and maintenance procedures; and 4) the manufacturer must submit a 510(k) pre-market notification before marketing the device or test. According to the Center for Devices and Radiological Health, 47% of all medical devices fall under this category. In addition, 95% of Class I devices (and a few in Class II) are exempt from the pre-market notification but still must meet other general controls, such as registration of their establishment and listing of devices with the FDA. 
• Class II covers 43% of medical devices and includes items such as motorized wheelchairs, toxoplasmosis tests, tests for drugs of abuse, and antinuclear antibody tests. Class II devices and tests are ones for which the general controls have not been deemed sufficient to ensure safety and effectiveness; therefore, they are subject to special controls such as special labeling, mandatory performance standards, and post-market monitoring. The majority of chemistry and hematology analytes, such as bilirubin, albumin, glucose, folic acid, and hematocrit, are Class II tests. Laboratory instruments, such as automated CBC devices, are in this class as well. 
• Class III, the most stringent category, includes 10% of medical devices. These devices are capable of sustaining or supporting life or are implanted into the patient. This class also includes devices or tests for which there is not enough information about their safety and effectiveness to protect the public with just general or even special controls. These devices, which can present a potential risk or illness or injury to the patient, include items such as implantable pacemakers and breast implants. In the laboratory, hepatitis and cancer diagnostic tests are categorized as Class III for that use.

As an example of intended use, a test used in conjunction with other laboratory or clinical methods to monitor for cancer recurrence could be Class II; the same test used by itself to diagnose or screen for cancer would likely be Class III.