Three codes, one patient, one calendar year, and a denial that cannot be fixed by rebilling. This is the costliest sequencing error in primary care.
G0402 — the Welcome to Medicare visit. Once per lifetime, and only within the first 12 months of Part B enrolment.
G0438 — the initial Annual Wellness Visit. Once per lifetime, and not until 12 months after Part B started.
G0439 — the subsequent AWV. Every year after that, 366 days apart.
Why this one hurts more than an ordinary denial
Most coding errors cost you a correction and a resubmission. This one costs the whole visit.
G0402 and G0438 are once-per-lifetime codes. If you bill G0438 for a patient who already had it two years ago at another practice, it denies — and there is no version of that claim that pays. You cannot rebill it as G0439 for the same date and expect it to hold, because the AWV interval is measured from the last paid wellness visit, not from your attempt.
The patient walked in, the staff did the full work — health risk assessment, medication review, cognitive screen, prevention plan — and none of it is billable. And because AWVs run on an annual clock, that patient is usually not eligible again for another year.
The four sequencing traps
1. New patient, unknown history. The patient had an AWV at their previous practice. You bill G0438, it denies as already-used, and you learn their history from a remittance advice.
2. G0402 billed past the 12-month window. The Welcome to Medicare visit expires. Bill it in month 13 and it denies outright — it should have been G0438.
3. G0438 billed too early. Inside the first 12 months of Part B, the initial AWV is not yet available. That visit was a G0402.
4. G0439 billed 364 days after the last one. The interval is a full 11 months plus — the next AWV is payable in the month after 11 full months have passed. Two days early and it denies.
The bigger loss nobody counts
After enough of these, front-desk and clinical staff stop scheduling wellness visits for any patient whose history is unclear. It is not a policy decision; it is scar tissue.
What follows is worse than the denials. AWVs are the entry point for chronic care management, transitional care, and the risk-adjustment documentation that drives every value-based contract you hold. A practice that quietly stops doing AWVs is not just losing the visit fee — it is losing the mechanism that surfaces everything else.
Run this on your own data
1. Pull 12 months of denied G0402, G0438 and G0439 and sort by denial reason. Separate “already used” from “too early.” The first is an eligibility-checking failure; the second is a scheduling-interval failure. They have completely different fixes and most practices treat them as one problem.
2. Count AWVs per 1,000 Medicare patients, by provider, over 24 months. A provider whose rate falls and stays down has stopped offering them. That is the scar tissue, and it is the largest number on this page.
3. Check whether anyone runs the eligibility query before the visit. Medicare will tell you the last wellness visit date and which codes remain available — before the patient arrives. If nobody is checking, every one of these denials was preventable at zero cost.
Find something and want the fix? Reply and say so. Find nothing? Genuinely worth knowing for certain.
When the code isn’t the real problem
If your AWVs are paying but the revenue still looks thin, the issue is the same-day E/M. A wellness visit and a medically necessary problem visit on the same day are both billable when the E/M is separately identifiable and carries modifier 25. Most practices bill only the wellness visit. That is a different leak, and usually a larger one — but fix the sequencing first, because an unpaid AWV makes the modifier 25 question irrelevant.