Internal medicine practices manage some of the most complex patient populations in outpatient medicine — patients with multiple chronic conditions, complex medication regimens, frequent specialist referrals, and high hospitalization rates. Despite this complexity, most internal medicine practices consistently underbill their services and miss multiple billable codes that could add $50,000–$200,000 in legitimate annual revenue without seeing a single additional patient.

This guide covers the 2021 E/M coding guidelines, Chronic Care Management billing, Annual Wellness Visit requirements, and Transitional Care Management codes — the four biggest revenue opportunities in internal medicine that most practices are not fully capturing.

2021 E/M Office Visit Coding — The Rules That Changed Everything

Effective January 1, 2021, the AMA completely revised the documentation guidelines for E/M office visit codes 99202–99215. The old system required documenting specific numbers of history elements, physical exam systems, and medical decision making components. The new system is simpler — and in most cases allows internal medicine physicians to bill significantly higher levels than they were billing before.

Under the 2021 guidelines, E/M code selection is based on either:

• Medical Decision Making (MDM) — the complexity of the problems addressed, the amount and complexity of data reviewed, and the risk of complications and management options, OR
• Total Time — the total time spent on the day of the encounter, including all face-to-face and non-face-to-face activities (documentation, ordering tests, reviewing results, counseling, etc.)

Established Patient E/M Codes (Most Commonly Used)

Chronic Care Management (CCM) — The Biggest Missed Revenue Opportunity

Medicare's Chronic Care Management program pays physicians monthly fees for providing non-face-to-face care management services to patients with two or more chronic conditions. Despite being available since 2015, the majority of eligible internal medicine practices are not billing CCM — leaving an estimated $62–$130+ per patient per month uncollected.

CCM Eligibility Requirements

• Patient must have two or more chronic conditions expected to last at least 12 months or until death
• Chronic conditions must place the patient at significant risk of death, acute exacerbation, functional decline, or hospitalization
• Patient must provide written consent for CCM services — which must be documented in the chart
• A comprehensive electronic care plan must be created and shared with the patient
• 24/7 access to care team members for urgent needs must be provided
• Each month, the qualifying time must be documented in the medical record

CCM CPT Codes

• 99490 — CCM services, first 20 minutes of clinical staff time per calendar month — approximately $62/month in Medicare reimbursement
• 99439 — CCM services, each additional 20 minutes of clinical staff time per calendar month (add-on to 99490) — approximately $47/month each
• 99487 — Complex CCM services, first 60 minutes of clinical staff time per calendar month — requires moderate or high complexity MDM
• 99489 — Complex CCM services, each additional 30 minutes of clinical staff time (add-on to 99487)
• 99491 — CCM services, first 30 minutes personally provided by physician or other qualified health professional (not clinical staff)
• 99437 — CCM services, each additional 30 minutes personally provided by physician (add-on to 99491)

Annual Wellness Visit (AWV) — Not the Same as a Physical

Many patients and even practice staff confuse the Medicare Annual Wellness Visit with a routine physical examination. They are different services with different billing codes. The AWV is a preventive visit focused on health risk assessment, maintaining a health record, advance care planning, and referrals for preventive screenings — it does not include a comprehensive physical examination.

AWV CPT Codes

• G0402 — Initial Preventive Physical Examination (IPPE, "Welcome to Medicare" visit) — one-time benefit for new Medicare beneficiaries within 12 months of Part B enrollment. Includes 10-year cardiovascular risk screening, depression screening, cognitive assessment, and review of functional ability.
• G0438 — Annual Wellness Visit, initial (first AWV after the Welcome to Medicare visit)
• G0439 — Annual Wellness Visit, subsequent (every year after the first AWV)

Transitional Care Management (TCM) — Post-Discharge Billing

When an internal medicine physician manages a patient's care after discharge from an inpatient hospital, observation stay, skilled nursing facility, or partial hospitalization, Transitional Care Management codes can be billed. These codes reimburse significantly more than a standard office visit and represent one of the most consistently underbilled services in internal medicine.

TCM Requirements

• Contact with the patient (or caregiver) must be made within 2 business days of discharge — by phone, face-to-face, or electronic means
• A face-to-face visit must occur within 14 days of discharge for 99495, or within 7 days for 99496
• The physician must review the discharge summary and coordinate care with other providers during the post-discharge period
• Only one TCM code per discharge episode can be billed

TCM CPT Codes

• 99495 — TCM with moderate complexity medical decision making — contact within 2 business days, face-to-face visit within 14 days of discharge — approximately $175–$215 Medicare reimbursement
• 99496 — TCM with high complexity medical decision making — contact within 2 business days, face-to-face visit within 7 days of discharge — approximately $240–$285 Medicare reimbursement

Top Internal Medicine Billing Errors

• Defaulting to 99213 for all established patient visits rather than selecting the code based on 2021 MDM criteria
• Not billing CCM codes for eligible Medicare patients with 2+ chronic conditions — the most significant missed revenue in most IM practices
• Confusing G0438/G0439 AWV codes with routine physical exam codes
• Not billing an E/M with modifier 25 when addressing a separate problem on the same day as the AWV
• Missing TCM billing after patient hospital discharges — this requires a proactive workflow to capture every qualifying discharge
• Billing 99213 when total documented time supports 99214 or 99215 under the time-based coding option
• Not documenting the specific time spent when using time-based E/M coding — "approximately 30 minutes" is not sufficient; document specific start/end times or total time

Frequently Asked Questions