Glossary
DEA number
A DEA number is the nine-character registration identifier the DEA issues to a prescriber or a pharmacy: two letters, then seven digits. The second letter is the surname initial, and the last digit is a check digit.
A DEA number is the registration identifier the Drug Enforcement Administration issues to anyone who handles controlled substances — a prescriber, a pharmacy, a distributor. It is nine characters: two letters followed by seven digits, and it is not the same thing as a state license to practice; the DEA number says what the registrant may do with controlled substances, the state license says they may practice at all.
Each part of the number carries information. The first letter is the registrant type: A, B or F is a standard practitioner or hospital, M is a mid-level practitioner — a nurse practitioner or a physician assistant — and X marked a DATA-waiver prescriber for buprenorphine (since the MAT Act of 2023 the waiver requirement has changed, so old teaching on X numbers is a place to check the current rule rather than a fact to recite). The second letter is the first letter of the registrant's surname, so a prescription from Dr. Alvarez carrying a number whose second letter is P is worth a second look. The seven digits end in a check digit.
The check digit is the one piece of arithmetic a technician can do at the counter. Add the digits in the odd positions to twice the sum of the digits in the even positions, then take the last digit of the total: that is the check digit the number must end in. If it does not, the number was mistyped or invented. The check digit is a screen, not a verdict — a forged number can carry a correct check digit, and a number that passes says nothing about whether the prescriber is registered today, or whether the prescription is for a legitimate medical purpose. That last judgment is the pharmacist's, under the corresponding responsibility rule.
Taught in
Related terms
- national drug code — The National Drug Code is the identifier a drug package carries in three segments — labeler, product, package. Labels print it as 10 digits in one of three layouts; billing systems key on an 11-digit padded form.
- days supply — Days supply is how long a dispensed quantity is meant to last: the quantity divided by the amount taken per day. It comes from the sig, not from the size of the package.
- high-alert medication — A high-alert medication is one that bears a heightened risk of significant harm when it is used in error — insulin, heparin, opioids, concentrated electrolytes. The risk is the harm, not a higher error rate.
Source: PTCB — PTCE Content Outline, effective January 6, 2026 (the KA 1.2 statement "Therapeutic duplications", the KA 2.2 and 2.3 statements on controlled substances and prescription requirements, the KA 4.3 and 4.4 statements on NDC, lot, expiration and returns, and the KA 3.1/3.2 error-prevention statements, quoted verbatim); FDA label and NDC data read through openFDA and DailyMed; ISMP (the high-alert medication definition and the error-prone abbreviation list); USP <795> and <797>; the DEA Pharmacist's Manual (outline accessed 2026-10-03, verbatim; every fact below restates this course's own guides, which carry the per-source citations on their own pages (FDA, ISMP, USP and DEA each publish on its own schedule))