Title: Coding
Standard #:


Issued: 12/01/1997 Reviewed/Revision Date: 08/21/2000, 10/06/2009, 11/01/2011, 12/09/2014


Current Procedural Terminology (CPT) is a set of codes, descriptions, and guidelines maintained by the American Medical Association through the CPT Editorial Panel.  The CPT code set describes medical, surgical, and diagnostic services performed by physicians and other health care providers.

Current Dental Terminology (CDT) is a code set with descriptive terms developed and updated by the American Dental Association for reporting dental services and procedures to dental benefit plans.

Modifiers provide the means to report or indicate that a service or procedure that has been performed has been altered by some specific circumstance but not changed in its definition or code.  Modifiers enable health care professionals to effectively respond to payment policy requirements established by other entities.


Providers are responsible for selecting and/or approving the most current and appropriate procedural service code (CPT-4 or CDT) with the highest degree of specificity and, if applicable, the appropriate modifier(s) and the most appropriate diagnosis code.

Providers must sign, approve or authenticate that (1) the service was personally performed or supervised by the provider, (2) the patient’s diagnosis is recorded in his or her medical record, and (3) type, scope and extent of services furnished meet the CPT-4 or CDT code descriptor matching the billing code.  Even if qualified abstractors are performing coding services, the providers are responsible for ensuring correct coding and modifier assignment.  Therefore, all charges should be reviewed carefully by the provider to ensure appropriate billing.

For Evaluation and Management (E&M) services, providers must select the appropriate level of service.  To accomplish this objective, providers must determine the complexity of the service rendered based on the three E&M components: (1) patient history; (2) physical exam; (3) medical decision making and record accurately in the patient’s medical record.

Providers must review code narratives in the current CPT/CDT procedural book if there is a question or contact the Compliance Liaison or Compliance Monitor for clarification and or assistance.

The CPT/CDT procedural code selected must meet or exceed the CPT/CDT procedural book narrative.


The Office of Inspector General has issued guidance in the proper use of modifiers.  The provider must document in the clinical record and on the encounter form if a service or procedure that has been performed has been altered by some specific circumstance but not changed in its definition or code (i.e., if a service or procedure has been increased or reduced, or only performed in part).  This will indicate whether or not a modifier should be appended to the CPT/CDT code.  Before a claim is submitted to a payer, it must be determined whether or not a modifier should be used.  Definitions and descriptions of modifiers can be found in the CPT/CDT Manual.


Providers and coding personnel in each clinical department will utilize the approved and current diagnosis coding guidelines for provider services as listed below:

  • Providers must first list the diagnosis code for the primary condition, problem, or other reason for encounter/visit shown in the medical record.  Additional codes that describe any coexisting conditions should also be documented.  If there is no specific diagnosis, report the sign, symptom or abnormal test result precipitating the visit as the principal diagnosis.
  • Codes must be utilized at their highest level of specificity.  Example: Assign three digit codes only if there are no four digit codes within that code category; assign four digit codes only if there is no fifth digit sub-classification for that category.
  • Do not code diagnoses documented as “probable,” “suspected,” “questionable” or “rule out” as if they were established.  Rather, code the condition(s) to the highest degree of certainty for that encounter/visit, such as symptoms, signs, abnormal test results or other reason for the visit.
  • Chronic disease treated on an ongoing basis may be coded and reported as many times as the patient receives treatment and care for the condition(s).
  • For surgery, code the diagnosis for which the surgery was performed.  If the post-operative diagnosis is known to be different from the preoperative diagnosis at the time the claim is filed, select the postoperative diagnosis for coding.
  • Code all documented conditions that coexist at the time of the encounter/visit and that require or affect patient care, treatment or management.  Do not code conditions previously treated or no longer existing.  When multiple specialists are providing services to the same patient, it is imperative that each specialty designates the specific problem or complaint for which the specialist is seeing the patient.


The provider is responsible for matching or linking the CPT/CDT codes to the corresponding Modifiers and/or Diagnosis codes.  This is especially pertinent when the provider is treating patients with multiple diagnoses and/or is billing for multiple CPT/CDT codes on the same day.

Questions regarding policies, procedures or interpretations should be directed to the USC Office of Culture, Ethics and Compliance at (323) 442-8588 or USC Report & Response at (213) 740-2500 or (800) 348-7454.