Surgery Modifiers: RT, LT, 50, F/T/E, 22, 51, 52, 53, 73, 74

A modifier is a two-character code (numbers, letters or both) added to a CPT or HCPCS code. It tells the payer something the code alone can't: the side or digit, extra or reduced work, more than one procedure, or a procedure that was stopped. It never changes what the code means.

Some modifiers change payment (pricing modifiers, such as 50, 22 and 52). Others only identify where or how (informational modifiers, such as RT, LT and F1). No modifier overrides the CPT descriptor, NCCI edits, medical necessity or payer policy.

Where?

RT · LT · 50 · FA–F9 · TA–T9 · E1–E4

Side, digit or eyelid

How much work?

22 · 52

More or less than usual

How many? Finished?

51 · 53 · 73 · 74

Several procedures, or stopped early

Part 1 of 7

RT, LT and 50

Modifier	Meaning	Use
RT	Right side	A procedure on the right side only
LT	Left side	A procedure on the left side only
50	Bilateral procedure	The same procedure on both sides in the same session, when the code allows it

Example, total knee arthroplasty (27447): right knee only is 27447-RT, left knee only is 27447-LT, and both knees in the same session is 27447-50 when the payer allows it.

Medicare: one line with modifier 50

For Medicare physician claims, report a bilateral procedure once, on one line, with modifier 50 (manual §40.7). CPT's own guidance says two lines; Medicare doesn't follow that. Other payers may want RT and LT on two lines, so check their policy.

Whether modifier 50 applies, and how it's paid, depends on the code's bilateral surgery indicator in the Medicare Physician Fee Schedule:

Indicator	What it means	Payment
1	Bilateral adjustment applies	Up to 150% of the fee
0	Bilateral adjustment doesn't apply (the service is never "bilateral")	100%; don't use modifier 50
2	The code is already bilateral, by its descriptor or its RVUs	100%; don't use modifier 50
3	Bilateral adjustment doesn't apply; each side is paid in full (mostly imaging)	100% for each side

Done: RT, LT and bilateral 50

Part 2 of 7

Finger, toe and eyelid modifiers

When a code applies to a single digit or eyelid, these modifiers say exactly which one, more precisely than RT or LT.

Left hand

FAThumb
F1Index (2nd)
F2Middle (3rd)
F3Ring (4th)
F4Little (5th)

Right hand

F5Thumb
F6Index (2nd)
F7Middle (3rd)
F8Ring (4th)
F9Little (5th)

Left foot

TAGreat toe (hallux)
T12nd toe
T23rd toe
T34th toe
T45th toe

Right foot

T5Great toe (hallux)
T62nd toe
T73rd toe
T84th toe
T95th toe

Eyelids

Modifier	Eyelid
E1	Left upper
E2	Left lower
E3	Right upper
E4	Right lower

Example: a procedure on the right upper eyelid is reported with E3. When the code calls for a specific eyelid, use the E modifier rather than RT or LT.

Done: Fingers, toes and eyelids

Part 3 of 7

Modifier 22: increased procedural services

Modifier 22 means the work was substantially greater than the procedure usually requires: for example extensive adhesions that needed extra dissection, distorted anatomy, or unusual technical difficulty. It isn't a "difficult patient" modifier, and extra payment is never automatic.

The operative report should show:

What made the procedure unusually difficult
What additional work was done
Why it was needed
How it went beyond the usual procedure
The extra time, when relevant

Example

Documentation that supports modifier 22

"The patient had extensive adhesions from prior surgeries. Additional adhesiolysis and dissection, about 40 minutes, were needed to expose the operative site safely. This substantially increased the technical difficulty and work compared with the usual procedure."

Not enough on its own	Why
Obesity or a high BMI	The note must show how it increased the work
"Adhesions present"	Say how much extra dissection was needed and why
"Took 30 minutes longer"	Time needs a description of the extra work

Put 22 on the procedure that took the extra work, not automatically on the first line or on every code. For example, in a shoulder arthroscopy with rotator cuff repair, debridement and acromioplasty, if only the cuff repair was unusually difficult, only that code gets 22.

Done: Modifier 22: increased work

Part 4 of 7

Modifier 51: multiple procedures

Modifier 51 tells the payer that one surgeon did more than one procedure in the same session, so multiple-procedure payment rules apply. Medicare usually pays the highest-valued procedure in full and the others at 50%.

Medicare guidance points two ways, so follow your MAC:

The Claims Manual (§40.6) says to report the major procedure without 51 and the additional ones with 51.
Medicare claims systems also recognise multiple procedures without the modifier, and some MACs ask you not to add it. Noridian's JE Part B guidance, for example, says its system applies 51 to the right line automatically, while other jurisdictions list cases where you should add it.
Commercial payers each have their own rules, and a client may have written billing instructions.

Check	If not
More than one procedure, same surgeon, same session?	No 51. One code on the claim never needs it.
Each procedure separately reportable?	Check CPT instructions and NCCI edits first.
Is the code an add-on (+)?	Never add 51 to an add-on code.
Is the code modifier 51 exempt (CPT Appendix E)?	Don't add 51.
What do the payer and the client require?	Follow their written policy.

When surgeons of different specialties each do a different, unrelated procedure (for example in multiple trauma), the multiple-surgery rules don't apply between them.

Done: Modifier 51: multiple procedures

Part 5 of 7

Modifier 52: reduced services

Modifier 52 means part of the service was reduced or eliminated at the physician's choice, and no other code describes what was done. The note should say what was done, what was left out, and why. For Medicare, send a statement and the operative report; without them the MAC won't price the claim.

Two situations from coding practice:

Codes described as bilateral. Some codes are bilateral by definition (CPT 30465, repair of nasal vestibular stenosis, is one). When only one side is done, RT or LT doesn't fit, so check the code's CPT instructions for unilateral reporting, which may direct modifier 52. 30465 and 30468 are different codes; don't swap them.
Tonsillectomy. Pick the code by whether the adenoids are removed and by age. There's no general CPT rule that removing one tonsil needs modifier 52, so check the current instructions and payer policy.

Code	Description
42820	Tonsillectomy and adenoidectomy, younger than 12
42821	Tonsillectomy and adenoidectomy, age 12 or over
42825	Tonsillectomy, primary or secondary, younger than 12
42826	Tonsillectomy, primary or secondary, age 12 or over

Not finished? 52, 53, 73 or 74

Modifier	Who reports it	When
52	Physician (and some facility claims)	Service reduced by choice; what was done is still described by the code
53	Physician	Procedure started and then stopped because of extenuating circumstances or a threat to the patient's well-being
73	Hospital outpatient or ASC	Procedure stopped before anesthesia was given, after the patient was prepared
74	Hospital outpatient or ASC	Procedure stopped after anesthesia was given or after it started

Modifier 53 isn't used for an elective cancellation before the patient is induced or prepped in the operating room. Don't reach for 52 every time a procedure wasn't completed: the reason it stopped and the claim type decide the modifier.

Done: 52 vs. 53, 73 and 74

Part 6 of 7

Common mistakes

Myth	Fact
F8 is the left thumb	FA is the left thumb. F8 is the right ring finger.
T8 is the left great toe	TA is the left great toe. T5 is the right great toe; T8 is the right 4th toe.
Every procedure on both sides gets 50	Check the descriptor and the bilateral indicator (0, 1, 2 or 3).
Obesity or adhesions always support 22	Only documented, substantially greater work does.
22 goes on the first CPT code	It goes on the procedure that took the extra work.
22 can never be used on facility claims	Too broad. Check the claim type and payer rules.
Always add 51 from the second line on	Depends on the MAC or payer. Never on add-on or 51-exempt codes.
52 always pays 50%	The payer decides after review.
Every unfinished procedure is 52	53 (physician) or 73/74 (facility) may fit better, depending on why it stopped.

Before you add a modifier

Does the CPT code allow or need this modifier?
Does the operative report name the exact side, digit or eyelid?
Is it really bilateral, or does the code already include both sides?
For 22: is the extra work described, not just a diagnosis or a time?
For 51: have you checked add-on and exempt codes, NCCI edits and the payer's rule?
For 52: was the service reduced (52) or stopped (53, 73, 74)?
Have you followed the payer's current-year rules for this date of service?

Done: Common mistakes

Part 7 of 7

Practice cases

Decide the modifier before you open each answer.

CASE 01

Left shoulder

The operative report documents a procedure on the left shoulder only.

Reveal answer & rationale

LT, if the code allows laterality and the payer wants it.

CASE 02

Both knees, Medicare

A surgeon performs the same procedure on both knees in one session. The bilateral indicator is 1 and it's a Medicare physician claim.

Reveal answer & rationale

One line, one unit, modifier 50. Medicare pays up to 150% when the bilateral indicator is 1.

CASE 03

Right ring finger

A procedure is performed on the right ring finger.

Reveal answer & rationale

F8: right hand, 4th digit.

CASE 04

Left great toe

A procedure is performed on the left hallux.

Reveal answer & rationale

TA. Not T8, which is the right 4th toe.

CASE 05

Right upper eyelid

A procedure is performed on the right upper eyelid.

Reveal answer & rationale

E3.

CASE 06

Obesity alone

The patient is morbidly obese. The operative report doesn't describe any extra work or difficulty.

Reveal answer & rationale

No 22. Obesity alone isn't enough. Query the surgeon only if extra work may have been done but wasn't described, and don't suggest the wording.

CASE 07

Adhesions and 35 extra minutes

The report describes extensive adhesions from prior surgery, extra dissection to reach the target anatomy, and 35 extra minutes of work.

Reveal answer & rationale

22 may be supported. Confirm the report shows substantially greater work for that specific procedure, the code has a 0-, 10- or 90-day global period (Medicare), and send the statement and operative report.

CASE 08

Three procedures, automatic 51

Three procedures are done in one session. A trainee adds 51 to lines two and three without checking anything.

Reveal answer & rationale

Not automatically. Check that each is separately reportable (NCCI), skip add-on and 51-exempt codes, and follow the MAC or payer rule on whether to append 51.

CASE 09

One code with 51

Only one surgical code is reported, and the coder adds modifier 51.

Reveal answer & rationale

No. One procedure is never a multiple procedure.

CASE 10

Planned reduction

The physician chooses to perform only part of the planned service, and the report explains what was left out and why.

Reveal answer & rationale

52, if no other code describes what was done. Send the explanation and operative report.

CASE 11

Stopped for patient safety

The surgeon starts the procedure but stops because continuing would put the patient at risk.

Reveal answer & rationale

53 on the physician claim. The hospital outpatient or ASC claim uses 73 (before anesthesia) or 74 (after anesthesia).

CASE 12

Two different code numbers

A note mentions CPT 30465 in one place and 30468 in another for the same nasal procedure.

Reveal answer & rationale

Don't guess. Read the operative report and check both descriptors in the current CPT code set. Code what was actually done, and query if it's still unclear.

Done: Practice: 12 cases