Medical necessity in physical therapy: what payers require

Three documents decide whether a commercial physical therapy claim gets paid, and most of the practices billing against them have never opened one. Aetna last reviewed its physical therapy policy on June 2, 2026. UnitedHealthcare republished its commercial therapy policy on July 1. Cigna’s has been in force since December 15, 2025, and carries two names on the cover: Cigna and ASH, American Specialty Health, the contractor that reads the notes.

They are public. Two of them are specific down to the daily note. And they disagree on the one question that decides an appeal: how long a patient can go without measurable progress before the policy calls the care not medically necessary.

What does “medically necessary” mean to a commercial payer?

To a commercial payer, physical therapy is medically necessary when the documentation shows a condition that can still improve, goals written in measurable functional terms, successive objective measurements proving the improvement is happening, and care a home program could not replace. That is the common core of the UnitedHealthcare, Aetna and Cigna policies. Everything else is detail, and the detail is where claims die.

Cigna’s CPG 135 states the core most plainly. Services are medically necessary when “the individual’s condition has the potential to improve or is improving in response to therapy,” the program is “individualized, and there is documentation outlining quantifiable, attainable treatment goals,” and “improvement is evidenced by successive objective measurements.” They stop being medically necessary when “documentation fails to objectively verify subjective, objective and functional progress over a reasonable and predictable period of time.”

Notice what the profession says instead. APTA’s position on value-based physical therapist services holds that medically necessary services “improve, maintain, or slow the decline of the current level of function.” Maintain. Slow the decline. Aetna’s CPB 0325 says outright that physical therapy for a member “whose condition is neither regressing nor improving” is not medically necessary, with a narrow carve-out for setting up a maintenance program the patient then runs alone. Cigna draws the same line. The gap between those two definitions is the gap between what you know is good care and what the contract pays for. Your note has to live on the payer’s side of it.

The skilled-care test, at least, is the same everywhere. Cigna’s description of skilled services, “a service is not considered a skilled therapy service merely because it is furnished by a therapist,” matches Medicare’s Benefit Policy Manual nearly word for word. If the patient could do it safely at home, no payer wants to pay a therapist to watch.

How do UHC, Aetna and Cigna differ?

Mostly on clocks, and on who is reading. Here is what the three documents say, with their own dates.

Two rows in that table change how a front desk and a treating PT should work.

The Aetna clock starts at the evaluation. Aetna’s test is whether the member’s condition “can improve significantly” on measures like range of motion, strength, function or reported pain “within one month of the date that therapy begins,” with re-evaluation at least monthly. On a twice-a-week plan, that is eight visits to show a number moving.

And for Cigna, the reader is often not Cigna. Cigna’s own briefing to Wyoming legislators describes American Specialty Health as “delegated by Cigna Healthcare for network management, credentialing, contract administration, utilization management, medical necessity review, and claims processing.” APTA reported in 2023 that Cigna was expanding ASH into all or parts of 15 additional states that year, and that freestanding PT and OT practices in those areas must contract with ASH to stay in network for Cigna patients. ASH’s provider resource page says most newly contracted providers get “the first five (5) office visits in the calendar year” paid without a medical necessity review. After that, you have 180 days from the first date of service requiring review to submit the form, and ASH reviews it against its own library of more than 130 clinical practice guidelines. Your note has to satisfy a reviewer who has a guideline open in the other window.

What gets a commercial PT note denied?

The policies tell you. UnitedHealthcare says a revised plan of care “stating that the treating therapist has not made a meaningful update to support the need for continued services will not be accepted,” and that noting the percentage toward goals alone is not sufficient. Cigna says duplicated records “are not acceptable” because “it is not clinically reasonable or physiologically feasible that a patient’s condition will be identical on multiple encounters.” Then it adds the line that should worry anyone running a template: if the findings are identical across encounters, “it would be expected that treatment would end because the patient is not making progress.” A record made of checked boxes, circled list items or arrows “may result in an adverse determination.”

Then there is the home exercise program. Aetna: once “a home exercise program could be used for further gains, continuing supervised physical therapy is not considered medically necessary.” Cigna lists examples of exceptions that justify continuing, and they are specific: poor exercise technique that needs cueing and feedback, a lack of support at home to complete the program, cognitive impairment. If one of those applies to your patient, it belongs in the note in those words. If nothing like that applies, the payer reads visit nine the way it would read a gym membership.

How do you write one note that passes all three?

Pick one instrument per region and never switch it mid-episode. UnitedHealthcare wants progress reported “using consistent and comparable methods.” Cigna wants discharge documentation to carry “initial, subsequent, and final FOM scores.” Aetna wants objective data in the plan of care. A LEFS at the eval, at every progress report and at discharge satisfies all three; a LEFS at the eval and “tolerating well” at week four satisfies none. Our Medicare audits post covers the federal version of the same rule.

Write the skilled sentence every visit. Cigna and UnitedHealthcare both require “skilled ongoing reassessment” in the daily note, and Medicare’s contractors ask the same question: whether the skills of a therapist were needed, or whether “the services can be carried out by non-skilled personnel after sufficient training.” One plain sentence on what you did that the patient could not have done alone, and what you changed because of it, and the note is defensible. Omit it and a sound exercise program reads as supervision.

Write goals with a baseline, a target and a date. UnitedHealthcare’s wording is “functional, measurable, attainable, and time based.” Aetna and Cigna ask for “specific, quantitative and objective,” with an estimate of when. That turns “improve gait” into “walk 400 feet on level ground without an assistive device by October 3.”

Put the clock on the calendar. At two weeks, the Cigna note needs something moving. At four, the Aetna patient sits on the policy’s plateau line. At ninety days, the UnitedHealthcare plan of care needs a meaningful update. These dates are as schedulable as a recert, and the front desk can own them. An EHR should carry this for you: in Orion’s care plans, every goal has a baseline, a target value and a timeframe, and every measurement attaches to the goal it belongs to, so the history a reviewer asks for is the history the chart already keeps. Aurora captures AROM, MMT and special tests as measurements during the visit and carries the objective data forward, which leaves the skilled sentence and the judgment where they belong, with you.

Last, know the reader. For Cigna, that is ASH, with a five-visit runway and a 180-day submission window. For UnitedHealthcare Medicare Advantage, the plan of care goes through prior authorization first, which we covered separately. Either way, the note you wrote on visit two is the one that defends visit twelve.

None of this adds documentation. It is the same documentation, in the payer’s words, on the payer’s schedule. UnitedHealthcare’s policy runs ten pages, Cigna’s forty-four, Aetna’s is a web page, and all three are free. Open the one behind your biggest commercial contract this week and read its plan of care section against your last five evals. You will find the sentence you keep leaving out.