Diabetes and the Commercial Motor Vehicle Driver

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A 60-year-old man is sent by his new employer to your urgent care for a pre-employment Department of Transportation (DOT) physical to obtain clearance to drive a commercial motor vehicle. His medical history is significant for hypertension, for which he takes lisinopril. Otherwise, he is healthy, with normal vital signs. His physical exam is unremarkable, but the urine sample is notably positive for glucose. A fingerstick glucose test yields a measurement of 212 mg/dL. What is your next appropriate step to medically clear the patient to drive commercially?

Commercial motor vehicle (CMV) drivers are mandated by the Federal Motor Carrier Safety Administration (FMCSA) to receive a DOT physical examination by a licensed medical examiner. To qualify to perform the exam, physician assistants, advanced practice nurses, physicians, and chiropractors must complete an educational program and pass a written certification examination.1 Subsequently, the examiners are placed on a national registry—the National Registry of Certified Medical Examiners—with the mission to improve highway safety by determining whether a CMV driver’s health meets standards and guidelines set by the FMCSA.2

Under current guidelines, a DOT physical exam for a healthy CMV driver is considered valid for a maximum of 24 months. However, some diseases and medications require frequent follow-up, which can shorten the length of time a driver can be medically cleared to operate a CMV. Furthermore, certain conditions can disqualify the driver from meeting the necessary standards required for medical certification.

This case presentation offers the opportunity to review the requirements for evaluation and certification of a CMV driver with new-onset hyperglycemia and, ultimately, diabetes. In the United States, types 1 and 2 diabetes are estimated to affect 30.3 million people.3 About 33% of CMV drivers have been diagnosed with diabetes, which is significant since research has demonstrated an increased risk for crashes in individuals with diabetes, due to potential incapacitation from hypoglycemia.4-6

Thus, for practitioners and medical examiners, it is prudent to screen and manage diabetes in CMV drivers. In fact, over the past 15 years, federal regulations have stipulated that any driver with diabetes requiring insulin for control was disqualified from this type of work.7 This standard was developed in response to the increased risk for hypoglycemic reactions with the use of insulin. However, in September 2018, the FMCSA revised this regulation, permitting individuals with a stable insulin regimen and properly controlled diabetes to be qualified to operate a CMV. As a result, for drivers requiring insulin, the treating clinician must complete a standardized form within 45 days of the DOT exam, documenting management of the patient’s diabetes.8 For drivers with diabetes who do not require insulin, determinations are made on a case-by-case basis, with discernment of the driver’s ability to manage the disease and concurrently meet other standards for qualification.


Each CMV driver completes a standard medical history form that asks about specific medications, surgeries, or medical conditions, including diabetes or blood glucose problems. Subsequently, the driver and, ultimately, the medical examiner must expand upon and discuss every “yes” response to this questionnaire.

Regarding diabetes, the examiner should determine whether the disease is controlled by diet, pills, and/or insulin, with clarification of the doses, frequency, and prescriber. In addition, the examiner should review and document glucose control, blood glucose monitoring, history of hypoglycemic episodes, and episodes of fainting, dizziness, or loss of consciousness.7

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