The exam
CDL drivers must pass a DOT physical exam under 49 CFR §391.41 at least every 24 months. Some medical conditions (insulin-treated diabetes, cardiac disease, sleep apnea on treatment) require shorter certification cycles, typically 12 months.
The exam must be administered by a medical examiner listed on the National Registry of Certified Medical Examiners (NRCME). The list is at nationalregistry.fmcsa.dot.gov.
Common disqualifying conditions
Common conditions that complicate CDL certification: insulin-treated diabetes (requires Federal Diabetes Exemption process), uncorrected vision below 20/40 in either eye, hearing loss exceeding 40 dB at 1000 Hz in the better ear (with hearing aid if used), epilepsy without exemption, current alcoholism, and uncontrolled hypertension.
Many conditions allow continued certification with documentation, monitoring, and shorter recertification cycles. Drivers should not assume a condition disqualifies - consult the NRCME examiner.
How the certification flows
The medical examiner submits the certification result electronically to FMCSA NRCME within 24 hours of the exam. State CDL agencies pull the data via the Medical Certification Integration system (in integrated states) or via paper-card submission (in non-integrated states).
The driver receives a paper Medical Examiner Certificate. In integrated states this is largely a backup record; in non-integrated states the driver must submit it to the state DMV within the state's timeline (typically 10–15 days).