There is no federal DOT physical A1C limit. The qualification standards in 49 CFR 391.41 contain no A1C or HbA1c cutoff that automatically fails a driver [1]. What matters is the diabetes route and the examiner's assessment of control, stability, and safe CMV operation. Insulin-treated diabetes follows 49 CFR 391.46, which requires the MCSA-5870 from the treating clinician and an exam at least annually [2]. Diabetes not treated with insulin is handled through examiner judgment. With 10 weeks before recert, use the A1C trend as a reason to get your records and diabetes care in order, not as a number to chase on exam day.

Is there an A1C number that fails the DOT physical?

No. The federal physical qualification standards list 13 standards in 49 CFR 391.41(b), including insulin-treated diabetes, cardiovascular disease, respiratory dysfunction, high blood pressure, vision, hearing, drug use, and alcoholism. The diabetes standard is paragraph (b)(3), and it says a driver currently treated with insulin qualifies only by meeting 49 CFR 391.46. It does not state an A1C number [1].

That distinction matters because internet answers often turn a clinical lab result into a made-up pass or fail line. The rule does not do that. An A1C result can still be part of the medical picture your examiner reviews, especially when it is moving in the wrong direction or sits alongside symptoms, missed records, or an unstable treatment history. But the number alone is not a federal cutoff.

Your exam is a hands-on federal medical exam, not a lab contest. The examiner has to decide whether your current condition is compatible with safe operation. A rising A1C deserves attention before recert because it can signal that diabetes management needs work. It does not create a shortcut around the exam, and lowering a single result without stable care does not settle the safety question.

What changes when diabetes is treated with insulin?

Insulin treatment places you on a specific federal process. Under 49 CFR 391.46, the treating clinician who manages and prescribes insulin for your diabetes completes and signs the Insulin-Treated Diabetes Mellitus Assessment Form, MCSA-5870 [2]. The medical examiner then examines you at least annually and no later than 45 days after the treating clinician signs the form [2].

The certificate period is also defined on this route. An insulin-treated driver with at least 3 months of electronic blood glucose self-monitoring records can be certified for up to 12 months. Without those records, the driver can receive a certificate of up to 3 months while the record builds [2].

A1C still does not become the cutoff. The MCSA-5870 and the regular exam create a documented process around diabetes management. The treating clinician supplies the assessment, while the certified medical examiner makes the certification decision.

The current process replaced the old federal diabetes exemption program. FMCSA's final rule took effect November 19, 2018, and the MCSA-5870 assessment plus the regular exam replaced the former exemption route [6]. You do not need to build your plan around an old exemption answer.

What if I have type 2 diabetes and do not use insulin?

If your type 2 diabetes is treated without insulin, you do not enter the insulin-treated process only because you have diabetes. The federal rule specifically sends drivers currently treated with insulin to 49 CFR 391.46 [1][2]. For a driver on oral medication, the examiner evaluates the condition under the general qualification standard and decides whether it is controlled and compatible with safe CMV operation.

That is examiner judgment, not a fixed federal A1C number. The examiner may review your diabetes history, current treatment, records, symptoms, and whether the condition appears stable. The visit includes a health history review, blood pressure and pulse, vision and hearing checks, a urinalysis dipstick that screens for specific gravity, protein, blood, and glucose, and a hands-on exam of body systems [3].

Your A1C trend belongs in that file. If it is rising, bring the result and the plan from the clinician who manages your diabetes. Do not treat an older better result as if it describes your current condition. A clean record shows what changed, when it changed, and what is being done now.

A shorter certificate is possible when a condition needs monitoring. The certification period within the rules is the examiner's clinical judgment, not an automatic result of a particular A1C reading [3].

Does a rising A1C mean my med card is over?

No automatic result follows from a rising A1C. The federal standard does not publish a cutoff, so a trend by itself does not answer the certification question [1]. It does tell you that waiting for the exam may leave the examiner with an unresolved control issue.

You have 10 weeks, which is enough time to turn scattered information into a current record. Start with the result that is trending wrong. Make sure the clinician who manages your diabetes knows about the trend and has the current lab history. Keep the records that show what happened after that visit. The goal is not to manufacture an exam-day number. The goal is to show current care and a stable plan.

The same principle applies to other conditions. The blood pressure standard in 49 CFR 391.41(b)(6) says there can be no current clinical diagnosis of high blood pressure likely to interfere with safe CMV operation, but the regulation itself contains no numeric blood pressure cutoff [1]. Examiner guidance supplies staging for certification decisions [3]. Diabetes works similarly in the sense that the examiner must connect the medical condition to safe operation rather than apply an A1C pass line.

If your diabetes has impaired your ability to perform normal duties, federal rules require re-examination and recertification even when your current certificate has not expired [5]. That is a separate trigger from an ordinary recert appointment.

What paperwork should I bring to the diabetes exam?

Start with the records that answer the examiner's actual questions. For a non-insulin-treated driver, that means current diabetes information from the clinician managing the condition, recent lab history, and a clear list of current treatment. The point is not to submit a magic A1C. It is to show the present state of the condition and what is being done about a worsening trend.

For an insulin-treated driver, the key artifact is MCSA-5870. The treating clinician must complete and sign it, and the exam must take place at least annually and no later than 45 days after the signature [2]. Bring the electronic blood glucose self-monitoring records when you have them. At least 3 months of those records supports certification for up to 12 months under the insulin-treated process. Without them, the certificate can be up to 3 months while the record builds [2].

The exam itself is recorded on Medical Examination Report Form MCSA-5875. A qualified driver receives Medical Examiner's Certificate Form MCSA-5876, the wallet card commonly called the med card [4]. The exam must be performed by a medical examiner listed on the FMCSA National Registry of Certified Medical Examiners [4].

Before booking, use the FMCSA National Registry search to check the examiner. Roadworthy does not perform DOT physicals, employ or certify medical examiners, or issue medical certificates. Use the DOT physical hub for the exam process, DOT medical card guide for card paperwork, and DOT disqualifying conditions guide for the standards that can affect qualification.

Use this 2-path flow for your situation.

  1. Insulin-treated path
    1. Ask the treating clinician who manages and prescribes your insulin to complete and sign MCSA-5870 [2].
    2. Gather at least 3 months of electronic blood glucose self-monitoring records if you have them [2].
    3. Book the DOT exam with a medical examiner on the FMCSA National Registry [4].
    4. Complete the exam no later than 45 days after the treating clinician signs MCSA-5870 [2].
    5. Expect the medical examiner to examine and certify you at least annually [2][5].
    6. Understand that records can support a certificate of up to 12 months, while missing records can lead to a certificate of up to 3 months as the record builds [2].
  2. Not-insulin-treated path
    1. Pull your current A1C results and the earlier results that show the trend.
    2. Book the visit with the clinician managing your diabetes before the DOT exam.
    3. Ask for a current record of the condition, treatment, and response to the worsening trend.
    4. Bring that record to the certified medical examiner, who decides whether the condition is controlled and compatible with safe CMV operation [1][3].
    5. Bring MCSA-5875 information for the exam record and receive MCSA-5876 if the examiner certifies you [4].
    6. Follow the certificate period the examiner issues. A 2-year maximum exists for drivers who meet the general requirements, but examiners can certify for less when monitoring is needed [3][5].

What to do next

Written for a driver with type 2 diabetes on oral medication and recert 10 weeks away.

  1. Pull your latest A1C result and the earlier result that shows the trend.
  2. Book a diabetes visit this week with the clinician who manages your condition.
  3. Ask that clinician to document the current diabetes status, treatment, and response to the rising A1C.
  4. Create a home record of the information your clinician asks you to track, and keep it with the lab results.
  5. Use the FMCSA National Registry search to verify the medical examiner before booking [4].
  6. Schedule the DOT exam with enough time to bring the updated diabetes record.
  7. Bring your medication list, lab history, clinician record, and prior MCSA-5875 or MCSA-5876 paperwork to the exam [4].
  8. If insulin treatment begins, ask the treating clinician about MCSA-5870 and the 45-day signature window before the exam [2].
  9. Read the certificate period on MCSA-5876 and write its expiration date in your dispatch and home-terminal records [4].

Sources

  1. Cornell Law School LII, 49 CFR 391.41, physical qualification standards, accessed 2026-08-01, https://www.law.cornell.edu/cfr/text/49/391.41
  2. Cornell Law School LII, 49 CFR 391.46, insulin-treated diabetes standard, accessed 2026-08-01, https://www.law.cornell.edu/cfr/text/49/391.46
  3. FMCSA Medical Examiner's Handbook, 2024 edition, examiner judgment and certification guidance, accessed 2026-08-01, handbook-appendix
  4. Cornell Law School LII, 49 CFR 391.43, who performs the exam and the forms, accessed 2026-08-01, https://www.law.cornell.edu/cfr/text/49/391.43
  5. Cornell Law School LII, 49 CFR 391.45, who must be examined and when, accessed 2026-08-01, https://www.law.cornell.edu/cfr/text/49/391.45
  6. Federal Register via govinfo, diabetes standard final rule of September 19, 2018, accessed 2026-08-01, https://www.govinfo.gov/content/pkg/FR-2018-09-19/html/2018-20161.htm