To keep your active status on the Minnesota CNA registry you need to show proof of employment as a nursing assistant for a minimum of eight hours every two years since first obtaining certification. According to Minnesota regulations concerning nursing assistants, if you have not worked as a CNA for a period of 24 months, your status on the registry becomes inactive. If you wish to return to work as a CNA, you must call the Minnesota nurse aide registry and see if you need to retake the CNA exam. The registry may be reached at 800-397-6124 or at 651-215-8705. It can sometimes take more than 30 business days to get back on the registry if you let your license lapse.