LT Left Side – Used to identify procedures performed on the left side of the body. No effect on payment; however, failure to use when appropriate could result in delay or denial (or partial denial) of the claim.
RT Right Side – Used to identify procedures performed on the right side of the body. No effect on payment; however, failure to use when appropriate could result in delay or denial (or partial denial) of the claim.
22 Unusual procedural services – when the service(s) provided is greater than that usually required for the listed procedure.  It may be identified by adding modifier –22 to the procedure number.  A report is also required.
50 Bilateral procedure – Unless otherwise identified in the listings, bilateral procedures that are performed at the same operative session should be identified by adding the modifier -50 to the appropriate five digit code.  The number of services is always reported as “1”.
51 Multiple procedures – When multiple procedures, other than E/M services, are performed on the same day or at the same session by the same provider, the primary procedure or service may be reported as listed. The additional procedure(s) or service(s) are identified by adding modifier -51.  PAYMENT RULES:  The allowed is 100% of the fee schedule amount for the highest valued procedure, 50% of the fee schedule amount for the 2nd-5th procedures and “by report” for subsequent procedures.
EXCEPTIONS:
Multiple dermatology procedures:
The allowed amount is 100% of the fee schedule amount for the highest valued procedure, 50% for each subsequent procedure. 
52 Reduced services – Under certain circumstances a service or procedure is partially reduced or eliminated at the physician’s discretion. Under these circumstances the service provided can be identified by its usual procedure code and the addition of the modifier -52, signifying that the service is reduced. This provides a means of reporting reduced services without disturbing the identification of the basic service. Note: For hospital out-patient reporting of a previously scheduled procedure/service that is partially reduced or canceled as a result of extenuating circumstances or those that threaten the well-being of a patient prior to or after administration of anesthesia, see modifiers -73 and –74 (these modifiers are approved for ASC hospital out-patient use).
53 Discontinued procedure – Under certain circumstances, the physician may elect to terminate a surgical or diagnostic procedure. Due to extenuating circumstances or those that threaten the well being of the patient, it may be necessary to indicate that a surgical or diagnostic procedure was started but discontinued. This circumstance may be reported by adding the modifier -53 to the code reported by the physician for the discontinued procedure. Note: This modifier is not used to report the elective cancellation of a procedure prior to the patient’s anesthesia induction and/or surgical preparation in the operating suite. For outpatient hospital/ambulatory surgery center (ASC) reporting of a previously scheduled procedure/service that is partially reduced or canceled as a result of extenuating circumstances or those that threaten the well-being of the patient prior to or after administration of anesthesia, see modifiers -73 and -74 (modifiers approved for ASC and hospital out-patient use).
54 Surgical care only – Use with surgical codes when one physician performs a surgical procedure and another provides preoperative and/or postoperative management.
55 Postoperative care only – Use with surgical codes when one physician performed the postoperative management and another physician performed the surgical procedure.  The postoperative component may be identified by adding the modifier -55.  Payment will be limited to the amount allotted for postoperative services only.
58 Staged or related procedure or service during the postoperative period – This modifier should be appended to surgical procedures when the physician needs to indicate that the performance of a procedure or service during the postoperative period was: a) planned prospectively at the time of the original procedure (staged); b) more extensive than the original procedure; or c) for therapy following a diagnostic surgical procedure; e.g., a mastectomy follows a breast biopsy. Failure to use modifier when appropriate may result in denial of the subsequent surgery.
62 Two surgeons – When two surgeons work together as primary surgeons performing distinct part(s) of a single reportable surgical procedure, each surgeon should report his/her distinct operative work by adding the modifier -62 to the single distinct procedure code. Each surgeon should report the co-surgery once using the same procedure code. If additional procedure(s) (including add-on procedures) are performed during the same surgical session, separate codes may be reported without the modifier -62 added. Note: If a co-surgeon acts as an assistant in the performance of additional procedure(s) during the same surgical session, those services may be reported using separate procedure code(s), with modifier -80 or modifier.
66 Surgical team – Under some circumstance, highly complex procedures (requiring the concomitant services of several physicians, often of different specialties, plus other highly skilled specially trained personnel, various types complex equipment) are carried out under the “surgical team” concept.  Such circumstances may be identified by each participating physician with the addition of the modifier -66 to the basic procedure number used for reporting services.  The modifier should be used by each participating surgeon to report his/her services. When team surgery is medically necessary, the carrier will determine the appropriate allowances(s) “by report.”
76 Repeat procedure by same physician – The physician may need to indicate that a procedure or service was repeated subsequent to the original procedure or service. This circumstance may be reported by adding modifier -76 to the repeated procedure or service.
77 Repeat procedure by another physician – The physician may need to indicate that a basic procedure or service performed by another physician had to be repeated. This situation may be reported by adding modifier -77 to the repeated procedure or service.
78 Return to OR for related surgery during post-op period – Use on surgical codes only to indicate that another procedure was performed during the postoperative period of the initial procedure.  When this subsequent procedure is related to the first, and requires the use of the operating room, it may be reported by adding the modifier -78 to the relate procedure. Payment is limited to the amount allotted for intra-operative services only. Failure to use this modifier when appropriate may result in denial of the subsequent surgery.
79 Unrelated surgery during post-op period –  Use on surgical codes only to indicate that the performance of a procedure during the postoperative period was unrelated to the original procedure.  Failure to use this modifier when appropriate may result in denial of the subsequent surgery.
80 Assistant surgeon – Surgical assistant services may be identified by adding the modifier -80 to the usual procedure number(s). Medicare reimburses the assistant surgeon at 16% of the Medicare Physician Fee Schedule Data Base allowance for the surgical procedure.