Guides · Billing guide

Z71.3 and Z68 BMI codes: how dietitians pair them

By Javier Alvarez · Updated October 8, 2026 · 4 min read

ICD-10-CM codes update every October 1, and the FY2027 code set took effect on October 1, 2026. Check that each code is valid for the date of service and that it matches your payer's MNT policy. For the single-code pages, see Z71.3 and the Z68 BMI code finder.

What each code does

When the condition code must lead

Coverage for MNT is usually tied to a diagnosis. The first-listed code on the claim is the one payers check against their policy, so it should be the condition that makes the visit covered.

• Medicare and most Medicare Advantage plans: lead with diabetes (E08–E13, or O24.4x for gestational diabetes), chronic kidney disease not on dialysis (N18.x) or kidney transplant status (Z94.0, within 36 months). A claim led by Z71.3 or obesity alone is outside the benefit. See Medicare MNT coverage.
• Commercial plans that cover MNT for listed conditions: lead with the condition on their list. Many cover obesity, prediabetes, hyperlipidemia, hypertension or diabetes; the list varies by plan.
• Plans that cover preventive nutrition counseling: some plans pay Z71.3 first, often paired with a Z68 code or a cardiovascular risk factor, with no cost sharing as a preventive benefit. Whether that applies depends on the plan, so verify benefits before the visit. See preventive vs medical benefits.

In the ICD-10-CM tabular list, Z71.3 tells you to use an additional code for any associated underlying condition and for BMI when known. So even when Z71.3 leads, list the condition and the BMI after it.

Common condition codes in MNT

Code to the highest specificity the referring provider documented. If the referral only says "obesity" and you need a class code, ask the provider to document the class.

Adult BMI codes (age 20 and older)

Visits through September 30, 2026 still use Z68.1 (BMI 19.9 or less); from October 1, 2026 it is a header and no longer billable. Example: BMI 32.4 is Z68.32. BMI 27.0 is Z68.27.

Pediatric BMI codes (age 2 to 19)

Z68.55 and Z68.56 were added on October 1, 2024, and Z68.54 was narrowed at the same time. If you code children, make sure your code list is current for the date of service.

Rules that trip people up

• Z68 is never first. BMI codes are secondary only. A claim with a BMI code as the only or first diagnosis is a coding error and will reject or deny.
• Who can document what. The guidelines let you take BMI from a dietitian's documentation, but the related diagnosis (obesity, overweight, underweight) must come from the patient's provider. Keep the referral or provider note on file.
• Only code BMI when it matters. BMI should be reported only when there is an associated, reportable diagnosis such as obesity. In weight-related MNT that is almost always true, but don't add Z68 to a visit about food allergies with a normal BMI just because you measured it.
• No BMI codes in pregnancy. The guidelines say not to assign Z68 codes during pregnancy, so leave them off a gestational diabetes (O24.4x) claim.
• Use the current year's code set. Obesity class codes and new pediatric BMI codes arrived in October 2024, and the underweight split (Z68.18, Z68.19) in October 2026. Claims with deleted or not-yet-valid codes reject at the clearinghouse.
• Point the line to the right codes. On the CMS-1500 the diagnosis pointer (box 24E) should point to the covered condition first.

Worked example claim

A 30-minute follow-up for an adult with class 1 obesity and prediabetes, commercial plan that covers MNT for both.

CMS-1500 / 837P, diagnoses and line

All data in this example is invented for illustration.