Split/shared visits – where a physician and an advanced practice provider both participate in a facility E/M encounter on the same day – are governed by the substantive portion rules, and getting the documentation wrong silently reprices the encounter at 85% of the fee schedule.

What the Rule Requires

The visit bills under whichever clinician performed the substantive portion. The billing clinician must be identifiable from the documentation, and the encounter carries modifier FS in the facility setting. When the note does not establish the physician as the substantive provider, the encounter defaults to the APP – and Medicare pays APP services at 85% of the physician rate.

Why It Never Surfaces

The claim pays. There is no denial, no edit, no work queue entry. A hospitalist group running a physician-plus-APP model across a daily census can lose 15% on a large share of its encounters indefinitely, with every billing metric looking normal.

The Detection Report

Percentage of facility E/M encounters billed under APP NPIs versus physician NPIs, trended monthly, by site and by team. Sudden shifts that track staffing or documentation workflow changes are the finding. The companion report: FS-modifier encounters by billing clinician type.

The Fix Is Documentation, Not Coding

Where the physician genuinely performs the substantive portion, a structured attestation and a note template that captures it moves the encounter to 100% legitimately. Where the APP genuinely runs the visit, the 85% is correct – the point is that the rate should be determined by care delivery, not by template gaps.

Revenant Care runs billing operations for physician groups. Every report specification in this guide is available via our contact page – usable with or without us.