CPT codes describe most of the clinical care you provide—medical, surgical, diagnostic and other types of services. These are the codes you’ll use for office visits, preventive care and procedures and decision-making. They are:

• Maintained by the AMA, which updates the codes regularly to reflect changes in clinical practice.
• Formatted as five-character numeric or alphanumeric codes, with most codes using only numbers.
• Always begin with a number, which sets them apart from HCPCS Level II codes that start with a letter.
• Supported by two-digit modifiers that indicate that a service or procedure has been altered by a specific circumstance, or meet payer-specific billing requirements.

• 99204—This is a CPT code used for a Level 4 E/M visit with a new patient. It requires moderate medical decision making or 45 min. total time.
• 25 Modifier—This modifier is added to an E/M code (like 99204) when a significant, separately identifiable E/M service is performed by the same physician on the same day as another procedure. It tells the payer that the visit wasn’t just part of the procedure; it involved its own decision-making and documentation.

Often referred to as “hick-picks,” HCPCS Level II codes are used when CPT doesn’t include the item or service you need to report. These codes cover things like durable medical equipment, supplies and drugs. They are:

• Maintained by the Centers for Medicare and Medicaid Services (CMS), which is responsible for updating and overseeing the use of these codes.
• Five-character alphanumeric codes made up of a combination of letters and numbers.
• Always begin with a letter, unlike CPT codes, which start with numbers. HCPCS Level II codes start with a letter that typically reflects a category of service.
• Support two-character modifiers that give more detail about the service or item, such as location on the body or the type of provider delivering the care.

• G0008—This HCPCS Level II code is used to report the administration of the influenza virus vaccine to Medicare patients. It identifies the act of giving the vaccine, not the vaccine itself, which would be billed separately.
• AJ—This is a modifier used to indicate that the service was provided by a clinical social worker (CSW). Modifiers like AJ help clarify the type of provider delivering care, which may affect payment.
• F1—This is a modifier that specifies the left hand, second digit (i.e., the index finger). It gives more precise information about the location on the body where a service was performed. This is particularly helpful when billing for procedures involve limbs or digits.

Getting the code right isn’t just about payment, it ensures your documentation reflects the care you provided. Clean claims reduce denials, support compliance and help your practice track services, spot trends and identify care gaps.

Tip: Most EHR and billing systems let you run reports based on CPT and HCPCS codes, helping you monitor patient care and practice performance.

• ICD-10 codes are used to report diagnoses, symptoms and other reasons for patient encounters. These codes are added to insurance claims to explain the why behind a visit, helping ensure appropriate and supporting clinical and population health efforts. They are:
• Maintained by a federal committee made up of representatives from the CMS and the CDC’s NCHS.
• Alphanumeric codes made up of three to seven characters, with added digits providing more detail about the condition.
• Always begin with a letter, which corresponds to a general category or chapter of conditions (e.g., “E” for endocrine, “I” for circulatory).
• Part of the U.S. version called ICD-10-CM—where “CM” stands for Clinical Modification. This means the codes include more detail than the international version of ICD-10 to support better tracking and reporting in clinical settings.

• E11.42—This code comes from ICD-10-CM and is used for type 2 diabetes with diabetic polyneuropathy.
  • E identifies the chapter for endocrine, nutritional and metabolic diseases.
  • 1 specifies type 2 diabetes.
  • .42 adds the detail: diabetic polyneuropathy, a common complication affecting the peripheral nervous system.
• E10.649—This code indicates type 1 diabetes with hypoglycemia without coma.
  • E represents endocrine-related conditions.
  • 10 signals type 1 diabetes
  • .649 provides specificity—hypoglycemia as a complication, but without loss of consciousness.
• I50.42—This code is used for chronic combined systolic and diastolic congestive heart failure.
  • I places it in the circulatory system chapter.
  • 50 identifies heart failure.
  • .42 denotes both systolic and diastolic dysfunction in a chronic form.