How to Verify a DEA Number
Updated October 27, 2026
Checking that a prescriber’s DEA number is valid is a classic PTCB skill, part of Federal Requirements. A quick check can catch a forged prescription for a controlled substance. Here’s how it works, followed by free practice questions.
The format
A DEA number has 2 letters followed by 7 digits, for example AB1234563.
- The first letter shows the registrant type. For practitioners such as physicians and dentists it’s usually A, B, F or G; mid-level practitioners such as nurse practitioners and physician assistants usually have M.
- The second letter is usually the first letter of the prescriber’s last name at the time of registration.
The check digit formula
- Add the 1st, 3rd and 5th digits.
- Add the 2nd, 4th and 6th digits, and multiply that sum by 2.
- Add the two results.
- The last digit of that total must match the 7th digit of the DEA number.
Example: AB1234563
- 1 + 3 + 5 = 9
- (2 + 4 + 6) × 2 = 24
- 9 + 24 = 33
- The last digit is 3, which matches the 7th digit (3). The number passes the check.
Passing the check doesn’t prove a prescription is real; it only catches numbers that can’t be valid. Follow your pharmacy’s procedure if anything looks wrong.
Free DEA number practice questions
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How many characters are in a DEA number?Answer: BA DEA number has 2 letters followed by 7 digits; the last digit is the check digit.
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Dr. Lopez's DEA number is BL4213562. Does it pass the check digit test?Answer: D4 + 1 + 5 = 10. (2 + 3 + 6) × 2 = 22. 10 + 22 = 32, whose last digit, 2, matches the 7th digit. The second letter L also matches Lopez.
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What is the second letter of a practitioner's DEA number usually based on?Answer: AThe second letter is usually the first letter of the prescriber's last name when they registered.
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In the check digit formula, which digits are multiplied by 2?Answer: BAdd the 2nd, 4th and 6th digits and multiply that sum by 2, then add it to the sum of the 1st, 3rd and 5th digits.
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A DEA number's digits give a total of 47 in the check digit formula. What must the 7th digit be?Answer: BThe 7th digit must equal the last digit of the total, which is 7.
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Which first letter is usually assigned to a mid-level practitioner such as a nurse practitioner?Answer: CMid-level practitioners, such as nurse practitioners and physician assistants, usually have DEA numbers starting with M.
Related: controlled substances and federal law.
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