8-minute rule (counting MNT units)
MNT codes 97802 and 97803 are billed per 15 minutes of face-to-face time, so every claim needs a rule for turning minutes into units. The one most payers use is the midpoint convention: a unit is billable once more than half of it has passed.
| Face-to-face minutes | Units (15-minute codes) |
|---|---|
| 8-22 | 1 |
| 23-37 | 2 |
| 38-52 | 3 |
| 53-67 | 4 |
| 68-82 | 5 |
Where the name comes from: CMS wrote the "8-minute" counting method for timed therapy codes billed in 15-minute units (Claims Processing Manual, Ch. 5, §20.2). CMS's MNT billing section does not spell out a separate counting method (Ch. 4, §300), so dietitians generally apply the same midpoint thresholds. A commercial payer can publish its own unit policy or per-visit caps, and those override the table.
Two habits make units defensible: record start and stop times (or total face-to-face minutes) in every note, and never count charting, scheduling or pre-visit chart review. Under-billing is as real as over-billing: a 53-minute visit is 4 units, not 3.