What ICD-10 code the annual wellness visit uses
Medicare does not require a specific diagnosis code for the Annual Wellness Visit (AWV). Providers report it with the most appropriate diagnosis, and in practice that is a Z-code for a general adult medical examination: Z00.00 without abnormal findings, or Z00.01 with abnormal findings. The Centers for Medicare and Medicaid Services (CMS) sets the coverage and frequency rules for the AWV but leaves the diagnosis code to the clinician.
The AWV is a Part B preventive benefit, billed for the service itself with the AWV HCPCS codes G0438 for the initial visit and G0439 for each subsequent year. The ICD-10-CM code sits alongside those and describes the reason for the encounter. Because no specific diagnosis is mandated, payers vary: some accept Z00.00 for the AWV, and providers should follow the guidance of the specific payer they are billing.
Z00.00 vs Z00.01
Z00.00 is "Encounter for general adult medical examination without abnormal findings." Z00.01 is the same examination "with abnormal findings." Use Z00.01 when the visit uncovers a new or abnormal condition, and add the specific ICD-10 code for that finding alongside it.
The distinction is about what the exam turns up, not how thorough it was. An abnormal finding is a condition surfaced at the visit that warrants further evaluation or care. When you assign Z00.01, the code by itself does not tell the payer what was found, so the note has to also carry the specific ICD-10 code for the condition that made the exam abnormal. If the review is clean and nothing new surfaces, Z00.00 is the correct encounter code.
Coding chronic conditions at the AWV (HCC capture)
The AWV is the documentation opportunity to capture every chronic condition a member carries that year. Beyond the Z-code for the encounter, the visit should record the specific ICD-10 code for each chronic condition addressed, because those codes map to HCCs and set the member's RAF under CMS-HCC V28. A condition that is present but never documented and coded does not count toward the risk score, even when the patient clearly has it.
To be codable, a condition has to be supported in the note to the MEAT standard: Monitored, Evaluated, Assessed, or Treated. A diagnosis copied onto the problem list without that support will not hold up on audit. The AWV is the natural place to meet the standard because the visit already reviews the full problem list, medications, and history, which gives the clinician a reason to monitor or assess each active condition and document it.
Risk scores reset every year, so a member with diabetes or heart failure has to be recaptured each year for the condition to keep counting. Under V28, CMS removed many codes from the model and raised the documentation bar, which makes accurate capture at the AWV matter more, not less. The Z-code reports the visit; the chronic-condition codes are what drive an accurate RAF.
Common coding mistakes
Two errors recur on AWV claims. The first is reaching for a pediatric well-child code, Z00.121 or Z00.129, on a Medicare patient; those codes are for children and do not belong on an adult AWV. The second is coding only the Z00.00 or Z00.01 encounter code and stopping there, which leaves every chronic condition uncaptured and understates the member's RAF for the year.
How Pelica handles AWV coding
Pelica is the AI-native execution layer for value-based care: one live member record and a copilot beside every team that owns a risk-bearing contract. The Risk Adjustment copilot reads the chart at the AWV, maps each documented ICD-10 code to its HCC, and flags the conditions that are present in the data but not yet captured to the MEAT standard.
Most platforms show a coder which gaps exist. Pelica works the gap and follows up until it is resolved, so accurate capture happens during the visit cycle rather than after the submission window closes. At HealthCare Partners, the largest IPA in the country, risk-adjustment coordination dropped from 30 minutes to 3 minutes per member, the same team now covers two to three times more members, and the organization added 0.4 to its RAF in two quarters with no new headcount, across 175,000+ patients managed live.
Related terms
For the procedure codes that pair with these diagnosis codes, see AWV CPT codes. For what the visit covers and how often Medicare pays for it, see annual wellness visit. For how a documented condition becomes a risk score, see HCC.