Billing that protects the patient — and the practice.

1Document the why, not just the what

Medical necessity lives in the note. Tie every intervention to a functional goal the patient cares about (stairs, work, sport, getting out of a chair) and show why it needed your skill: what you assessed, cued, progressed, or changed.

• For Medicare, record the total timed-code minutes and the total treatment minutes (timed and untimed) for each visit.
• Write notes promptly. Late or missing notes are an easy denial.

Source: CMS MLN905365, therapy documentation requirements

2The 8-minute rule (Medicare timed codes)

For codes billed in 15-minute units, Medicare uses the total minutes of all timed services that day to decide how many units you can bill. If only one timed service is done, don't bill it for less than 8 minutes.

The pattern continues in 15-minute steps. Untimed codes (evals, group, unattended e-stim, hot/cold packs) are billed as 1 unit no matter how long they take, and their minutes don't count toward timed units. Some commercial payers count units differently, so check the policy.

Source: Medicare Claims Processing Manual, Ch. 5 §20.2

3KX modifier and the therapy threshold

Medicare doesn't have a hard therapy cap anymore, but it does have a yearly threshold. For 2026 it's $2,480 for PT and speech-language pathology combined (OT has its own $2,480 amount). Once a patient's PT/SLP services for the year go past it, add the KX modifier. That modifier is your statement that the care is medically necessary and the record backs it up. Claims over the threshold without KX are denied.

• Track each patient's year-to-date amount. Patients may have used some of it at another clinic.
• Medicare's separate targeted medical review threshold is $3,000. Not every claim above it gets reviewed, but documentation needs to be solid.
• If you expect Medicare may not cover a service, the patient should know before you provide it. That's what the Advance Beneficiary Notice (ABN) is for.

Source: CMS Therapy Services · CMS CR 14252 (CY 2026 KX thresholds)

4Plan of care certification and progress reports

• Initial certification: the physician/NPP signs the plan (or gives a verbal order) within 30 days of the first treatment day. The evaluation counts as the first day. A verbal order needs a signature within 14 days.
• Since 2025: if a signed, dated written order or referral is on file and you can show you sent the plan of care to that physician/NPP within 30 days of the initial eval, that can stand in for their signature on the initial plan. This doesn't apply to recertifications.
• Duration and recertification: a certification covers the plan's length or 90 calendar days, whichever is shorter. Recertify when the plan changes significantly, or at least every 90 days.
• Progress reports: at least once every 10 treatment days. Recertification dates don't change this.

Source: Medicare Benefit Policy Manual, Ch. 15 §220 · CMS CY 2025 PFS final rule summary · CMS MLN905365

5PTAs: supervision and the CQ modifier

• Supervision: starting January 1, 2025, Medicare allows general supervision of PTAs by PTs in private practice, matching the rule in institutional settings. Your state practice act may require more, and when it does, the stricter rule applies.
• CQ modifier: add CQ (along with GP) when a PTA provides a service entirely, or provides more than 10% of a service's minutes. This is called the "de minimis" or 10% standard. Medicare pays CQ services at 85% of the normal fee schedule amount.
• Don't use CQ when the PT provides the whole service, or when the PT and PTA treat the patient together at the same time. CMS also defines two narrow exceptions for the final unit(s) of a visit; see its billing examples.

Source: CMS MLN905365 · CMS CQ/CO billing examples · CMS CY 2025 PFS summary · CMS Therapy Services

6Prior authorization: check before you're in trouble

Many commercial and Medicare Advantage plans set their own authorization rules. Before the first treatment visit, find out what's approved: number of visits or units, the date range, and which codes are covered. Put the renewal on the calendar before the patient is one visit from the limit. That keeps care going without a gap and keeps the clinic from doing unpaid work.

7Denials and appeals: fix the process

• Keep a simple denial log sorted by reason code: missing auth, eligibility, a diagnosis/procedure mismatch, missing modifier (GP/KX/CQ), a late or missing certification, or documentation. Fix the step in your workflow that keeps causing it.
• Know the difference between a correctable claim error (fix and resubmit) and a coverage denial (appeal).
• Medicare Part B: the first appeal level is a redetermination by your Medicare Administrative Contractor. File it within 120 days of receiving the initial determination. Send the note that supports the service.

Source: CMS: First level of appeal (redetermination)

8Coding hygiene: bill the visit you actually gave

Choose codes and units that match what the note shows, at the complexity you really provided. Upcoding creates compliance risk. Habitual undercoding makes the clinic harder to sustain. Accurate coding protects the patient's benefits, your license, and the clinic.