The codes a prior authorization is written in

The obesity family

Class 1 to 3 (E66.811 to E66.813) entered the code set for fiscal year 2025. Plans whose published criteria predate that still name E66.01 and E66.9 only, which is worth knowing before assuming a newer, more precise code will be recognized.

The BMI codes

These carry the number a criterion is measured against. A criterion asking for the BMI before treatment is asking for the code recorded at baseline, not today's — the single most common reason a continuing request is refused.

Weight-related conditions

The BMI ≥ 27 route asks for one of these alongside the obesity code. Which conditions a plan accepts is the plan's own list; these are the codes they are written in.

When it is not a weight-loss prescription

These indications are on the labels themselves. A prescription written against one of them is not reached by the exclusion at Social Security Act §1927(d)(2), which is the provision a Medicaid or Part D denial for “weight loss” relies on.

If a denial cites the weight-loss exclusion against one of these, the appeal letter quotes the statute and the label back at it.

Where these come from

The code set itself and the statute a weight-loss denial is written under. Neither is quoted here from memory: the codes were read from the list, the exclusion from the Act.

• ICD-10-CM, Centers for Medicare & Medicaid Services — The diagnosis code set every US claim and prior-authorization form is written in, published annually by CMS and the CDC.
• Social Security Act §1927(d)(2), Office of the Law Revision Counsel — The statute itself, listing “agents when used for anorexia, weight loss, or weight gain” among the drugs a program may exclude.

Questions

What diagnosis gets a GLP-1 approved?

There is no code that approves anything. A plan's criteria name a BMI threshold, sometimes a weight-related condition alongside it, and sometimes something tried first; the codes are how the record states those facts to the plan. A request is refused when the record does not meet the criteria, or when it does and the form failed to say so — and the second is the common one.

Why do plans ask for two codes?

Because the obesity code and the BMI code carry different facts. E66.01 records morbid obesity; Z68.41 records that the measured BMI was 40.0 to 44.9. A criterion written as 'BMI at or above 40' is checked against the second, which is why 'BMI not documented' is a common refusal on a chart where the weight is plainly recorded.

Can I tell my prescriber which code to use?

You can tell them what your plan's criteria say — that is a document, and this site publishes the ones states publish. The code is theirs. A diagnosis is a clinical finding on a document they sign, and choosing one to reach a coverage threshold is not a coding question but a misrepresentation.

Does a diabetes or sleep apnea diagnosis change anything?

It changes which rule applies. The weight-loss exclusion a denial usually leans on — Social Security Act §1927(d)(2), which lets a program exclude 'agents when used for … weight loss' — does not reach a prescription written for a medically accepted indication the label carries. Tirzepatide has an obstructive sleep apnea indication, semaglutide a cardiovascular one, and both molecules carry type 2 diabetes on their diabetes-labeled brands.

Are these codes current?

Every code and description on this page was read from the CMS code set on 2026-09-12 and is quoted exactly, including the bracketed "[BMI]" the list itself carries. The obesity class codes E66.811 to E66.813 are newer than many plans' published criteria, which still name only E66.01 and E66.9.