Modifier 27 – Coding Guide 2026: Multiple Outpatient Hospital E/M Encounters on the Same Date

[!NOTE] Quick Reference

Quick Reference: Modifier 27

• Definition: Multiple outpatient hospital evaluation and management (E/M) encounters on the same date of service.
• Who Uses It: Hospital outpatient departments only (facility billing on UB-04). Physicians and other professional-side billers do not use Modifier 27.
• When to Use: When a patient receives more than one E/M encounter in different hospital outpatient departments (e.g., ED + hospital-based clinic) on the same calendar date.
• Claim Form: UB-04 (CMS-1450) only — not used on CMS-1500 professional claims.
• Payment System: Applies under the Hospital Outpatient Prospective Payment System (OPPS) and certain state Medicaid outpatient systems.
• Key Rule: Append Modifier 27 to the second (and any additional) E/M code(s) on the claim to signal each represents a distinct, separately payable encounter.

Modifier 27 is one of the most frequently misunderstood and misapplied modifiers in hospital outpatient billing. Unlike the majority of CPT modifiers that appear on professional (physician) claims, Modifier 27 is a facility-side-only tool used exclusively by hospital outpatient departments (HOPDs) to identify that a patient had multiple, distinct E/M encounters in separate outpatient settings of the same hospital or health system on a single date. Without it, the second and any subsequent E/M services on a UB-04 claim will be bundled, denied, or reduced — costing hospitals significant reimbursement under OPPS.

Definition & Official CMS Description

The official CPT descriptor for Modifier 27 is:

“Multiple outpatient hospital evaluation and management encounters on the same date.”

CMS introduced Modifier 27 specifically to address a structural billing challenge: because all services rendered within a single hospital’s outpatient departments on a single date are reported on one UB-04 claim, payers (particularly Medicare under OPPS) need a way to identify that two or more distinct E/M encounters took place — not one E/M with a duplicate entry error. The modifier does not indicate a higher level of service. It does not affect MDM, time, or the E/M level selection for either encounter. It is purely a claim integrity and payment trigger used to override the automatic bundling of same-day E/M services on a facility claim.

Why Modifier 27 is Facility-Billing Only

This is the single most important concept to master about Modifier 27. It exists because of the fundamental difference between how professional (physician) and facility (hospital) claims are structured:

• Professional Claims (CMS-1500 / 837P): A physician’s claim is inherently tied to one provider NPI and one encounter. If two different physicians see the same patient on the same day, they each file a separate CMS-1500. There is no bundling problem to solve. Physicians handle same-day E/M situations with Modifier 25 (for a procedure performed same day) — not Modifier 27.
• Facility Claims (UB-04 / 837I): A hospital submits one consolidated UB-04 per patient per billing period. If a patient visits the ED at 8 AM and a hospital-based cardiology clinic at 2 PM, both services appear on the same UB-04 claim. Without Modifier 27, automated claim adjudication systems will flag the second E/M code as a duplicate and bundle it or deny it.

[!WARNING] Critical Rule: If your billing staff ever appends Modifier 27 to a line on a CMS-1500 (professional claim), that is a billing error. Modifier 27 is exclusively valid on the UB-04 institutional claim form. Most clearinghouses and payers will reject or ignore it on a 1500 claim, but it can also trigger audits.

When to Append Modifier 27: Qualifying Scenarios

Modifier 27 is appropriate when all three of the following conditions are met:

flowchart TD
    A[Patient had E/M service in hospital outpatient department] --> B{Is the claim a UB-04 facility claim?}
    B -->|No| C[Do NOT use Modifier 27]
    B -->|Yes| D{Did the patient have 2+ E/M encounters on the same date?}
    D -->|No| C
    D -->|Yes| E{Were the encounters in different outpatient departments?}
    E -->|No| F{Same department, same provider, same complaint?}
    F -->|Yes| C
    F -->|No| G[Review documentation — may qualify if clinically distinct]
    E -->|Yes| H{Is each encounter supported by a separate clinical note?}
    H -->|No| I[Ensure separate documentation before billing]
    H -->|Yes| J[Append Modifier 27 to the 2nd and subsequent E/M codes]

• The claim is a facility (UB-04) claim from a hospital outpatient department.
• The patient had two or more separate E/M encounters in different outpatient departments of the same hospital entity on the same calendar date.
• Each encounter is a clinically distinct visit — different presenting complaints, different clinical decision-making, and ideally, different departments or clinic locations.

Qualifying Department Combinations (Examples)

When NOT to Use Modifier 27: Common Errors

[!WARNING] Misuse Alert: Applying Modifier 27 incorrectly is one of the top OPPS billing errors identified by RAC (Recovery Audit Contractor) auditors. Each of the following scenarios is a known problem area.

Do NOT Use Modifier 27 When:

• The patient had only one E/M encounter. Multiple procedure codes (CPT 99213 + a procedure like 93000) do not require Modifier 27. That situation may require Modifier 25 on the physician side, but not 27 on the facility side unless there is also a second, separate E/M visit.
• The two E/M encounters are for the same problem in the same department. For example, a patient who returns to the same ED department within hours for the same complaint is not a second “encounter” in the Modifier 27 sense.
• Filing on a CMS-1500 / professional claim. As described above, Modifier 27 has no recognized function on a professional claim.
• The provider is a freestanding clinic not part of a hospital. OPPS rules apply to hospital outpatient departments. Freestanding clinics bill under the physician fee schedule, not OPPS, and Modifier 27 does not apply.
• Using it to bypass a National Correct Coding Initiative (NCCI) edit. Modifier 27 is not an NCCI override modifier and cannot be used to unbundle services that are bundled under NCCI edits for other reasons.
• Applying it to the first E/M code on the claim. Modifier 27 is appended only to the second and any subsequent E/M codes — not to the primary (first) E/M service on the claim.

OPPS Reimbursement & APC Implications

Under the Hospital Outpatient Prospective Payment System (OPPS), E/M services are assigned to Ambulatory Payment Classifications (APCs). When the hospital correctly reports two E/M codes with Modifier 27 on the second, Medicare will pay separately for each qualifying E/M service at its associated APC rate.

How Payment Works Under OPPS

• First E/M code (no modifier, or with another applicable modifier): Paid at 100% of the APC rate.
• Second E/M code (with Modifier 27): Paid at a reduced rate — typically subject to OPPS packaging rules. Under Medicare, the second E/M may be paid at a discounted percentage depending on the APC status indicator assigned to that code.
• Additional E/M codes (each with Modifier 27): Similarly subject to OPPS packaging and discounting logic.

[!TIP] Revenue Integrity Tip: Even though the second E/M under OPPS may be paid at a discounted rate, it is nearly always better to report it with Modifier 27 than not at all. Failing to append Modifier 27 results in the second E/M being denied entirely or bundled into zero additional payment. Any partial payment is better than none, and accurately reflects the hospital’s resource utilization.

Revenue Codes

E/M services in the hospital outpatient setting are typically billed under the following revenue codes on the UB-04:

How to Report on the UB-04 (Step-by-Step)

Correct line-item reporting on the UB-04 is critical. Here is the standard reporting structure when a patient has two qualifying outpatient E/M encounters on the same date:

Step 1: Identify Each Distinct E/M Service

Confirm that both encounters meet the criteria: different departments, different clinical purposes, same calendar date, and reported on the same UB-04 claim.

Step 2: Report the First E/M Code — No Modifier 27

Enter the first (primary or chronologically first) E/M CPT code on its own revenue code line. Do not append Modifier 27 to this line. Apply any other applicable modifiers (e.g., Modifier 25, Modifier 91) as appropriate for that service.

Step 3: Report the Second E/M Code — Append Modifier 27

Enter the second E/M CPT code on a new revenue code line. Append Modifier 27 in the modifier field of that line. The modifier signals to the payer that this is a separate, distinct encounter — not a duplicate billing error.

Step 4: Report Additional E/M Codes (If Three or More Encounters)

Each additional E/M encounter beyond the first gets its own line with Modifier 27 appended.

Example UB-04 Line Structure (Simplified): Line 1: Rev Code 0510 | CPT 99213 | Date 01/15/2026 | No Modifier | Charge: $250 (First outpatient clinic E/M — hospital-based primary care, 9:00 AM) Line 2: Rev Code 0450 | CPT 99284 | Date 01/15/2026 | Modifier: 27 | Charge: $480 (Second E/M — Emergency Department visit, 3:00 PM, separate problem)

Documentation Requirements

While Modifier 27 is a facility billing tool and is not appended to physician notes, supporting documentation must still demonstrate that the two encounters were clinically distinct. In the event of an audit, the following documentation must be available and clearly support separate encounters:

• Two separate clinical notes — each with its own time stamp, presenting complaint, history, assessment, and plan. A single note covering both visits will not support two E/M charges.
• Different providers or departments — the notes should reflect different ordering providers, clinic locations, or departments. If the same physician sees the patient twice on the same day in the same department, this typically does not support Modifier 27 usage.
• Distinct diagnoses or problems — while not absolutely required, separate presenting complaints strongly support the medical necessity of two billable encounters. Using the same ICD-10 diagnosis for both lines will attract scrutiny.
• Registration records — hospital registration logs (ADT system) confirming two separate check-ins at two distinct departments or clinics on the same date provide strong corroborating evidence.

[!WARNING] Audit Red Flag: CMS Recovery Audit Contractors (RACs) specifically target claims where the same E/M CPT code appears twice on a UB-04 for the same date without adequate differentiation in the documentation. Always ensure the clinical records unambiguously reflect two separate encounters before applying Modifier 27.

Modifier 27 vs. Modifier 25: Understanding the Difference

Confusion between Modifier 27 and Modifier 25 is extremely common, especially for coding staff who split time between professional and facility billing. Here is a clear breakdown:

[!TIP] Key Takeaway: Modifier 25 = E/M + Procedure, same provider, same day, professional claim. Modifier 27 = E/M + E/M, different hospital departments, same day, facility claim. They solve different problems and are never interchangeable.

Comparison: Common Outpatient Modifiers Used with E/M (Facility Context)

Payer-Specific Rules (Medicare, Medicaid, Commercial)

Medicare (OPPS)

Medicare is the primary payer under which Modifier 27 was designed to function. Under the Hospital OPPS, Medicare will process the modifier in accordance with the CMS Claims Processing Manual, Chapter 4 (Part B Hospital), which governs outpatient hospital billing. Hospitals must ensure their chargemasters and coding staff are applying Modifier 27 consistently for qualifying same-day encounters.

Medicaid

Medicaid coverage of Modifier 27 varies significantly by state. Some state Medicaid programs follow OPPS logic and recognize Modifier 27; others do not. Hospitals should verify the applicable state Medicaid billing manual before relying on Modifier 27 for Medicaid claims. Contact your State Medicaid Agency or MAC (Medicare Administrative Contractor) for the most current guidance for your jurisdiction.

Commercial Payers

Many commercial (private) insurers do not follow OPPS payment logic for hospital outpatient services. Some may recognize Modifier 27 and pay accordingly; others may treat hospital outpatient services under their own fee schedules, rendering the modifier irrelevant or potentially triggering a manual review. Always check each payer’s provider manual or call the payer directly before implementing Modifier 27 for non-Medicare claims. Key payers to verify include:

• UnitedHealthcare (UHC)
• Anthem / Blue Cross Blue Shield (varies by state)
• Aetna
• Cigna / Evernorth
• Humana (including Humana Medicare Advantage plans)

[!WARNING] Medicare Advantage (MA) Plans: MA plans are required to cover services that traditional Medicare covers, but they may have their own claim adjudication systems that do not automatically recognize all CMS modifiers. If a hospital experiences denials from an MA plan for claims with Modifier 27, the denial should be appealed citing the CMS OPPS guidelines applicable to the service date.

Audit Risks & Compliance Considerations

Modifier 27 carries audit risk from both over-use and under-use. Compliance officers and revenue integrity teams should monitor for both patterns.

Over-Use Risk (Upcoding / False Claims)

• Applying Modifier 27 when only one E/M encounter actually occurred.
• Splitting a single encounter into two billable events simply to generate a second E/M charge.
• Failing to maintain two separate, distinct clinical notes to support each billed encounter.
• Using Modifier 27 when the patient was seen by the same provider in the same clinic twice for the same complaint — a single encounter with a follow-up call or check does not qualify.

Under-Use Risk (Revenue Leakage)

• Failing to recognize and append Modifier 27 when a patient legitimately had two separate outpatient encounters, resulting in the second E/M being denied or bundled to zero payment.
• Revenue cycle staff unfamiliar with the modifier deleting the second E/M code rather than adding the modifier when it edits on the claim scrubber.
• Chargemaster configurations that do not auto-suggest Modifier 27 when two E/M codes appear for the same patient on the same date.

RAC and OIG Oversight

The OIG Work Plan and CMS RAC programs have historically identified same-day E/M billing in hospital outpatient settings as an area of vulnerability. Hospitals should conduct periodic internal audits of claims where Modifier 27 was used and confirm that supporting documentation exists for each billed encounter.

Complex Clinical Scenarios

Scenario 1: Emergency Department Visit Followed by Scheduled Clinic Visit

Patient: A 68-year-old Medicare patient with COPD presents to the hospital ED at 7:30 AM with acute dyspnea. She is evaluated, treated with nebulizers and steroids, and discharged at 11:00 AM. She had a previously scheduled follow-up visit in the hospital-based pulmonology clinic at 1:30 PM the same day, which she attends. E/M Codes: Line 1: CPT 99284 (High complexity ED visit) | Rev 0450 | No Modifier 27 Line 2: CPT 99213 (Low-moderate complexity outpatient visit) | Rev 0510 | Modifier 27 ICD-10: J44.1 (COPD with acute exacerbation) on Line 1; J44.1 or J44.9 on Line 2. Coding Rationale: Two distinct outpatient encounters, two separate departments (ED and pulmonology clinic), supported by two separate clinical notes and two registration events. Modifier 27 correctly appended to Line 2. Medicare pays Line 1 at full ED APC rate and Line 2 at its discounted outpatient clinic APC rate.

Scenario 2: Dual Hospital-Based Clinic Visits, Different Specialties

Patient: A 55-year-old with Type 2 Diabetes and end-stage renal disease (ESRD) is seen in the hospital-based nephrology clinic at 10:00 AM to review recent labs and adjust dialysis parameters. In the afternoon, he is also seen in the hospital-based ophthalmology clinic for a scheduled diabetic eye exam. E/M Codes: Line 1: CPT 99214 (Nephrology) | Rev 0510 | No Modifier 27 Line 2: CPT 99213 (Ophthalmology) | Rev 0510 | Modifier 27 ICD-10: N18.6 (ESRD) + E11.65 (DM with hyperglycemia) on Line 1; E11.3519 (Diabetic macular edema) on Line 2. Coding Rationale: Different specialists, different clinical problems, separate notes, same hospital campus. Classic Modifier 27 use case. The distinct ICD-10 codes on each line further support medical necessity for each encounter.

Scenario 3: Common Mistake — Modifier 27 Used Incorrectly for a Procedure

Incorrect Scenario: A patient is seen in the hospital-based orthopedic clinic (one encounter only). The provider evaluates the patient (CPT 99213) and then administers a cortisone injection to the knee (CPT 20610) during the same visit. The billing staff appends Modifier 27 to the 99213 line, thinking this separates the E/M from the procedure. Why This Is Wrong: Modifier 27 is not used to separate an E/M from a same-day procedure on a facility claim. There is only one encounter here. The appropriate modifier in this scenario on the professional claim would be Modifier 25. On the facility UB-04, the hospital typically does not need a modifier to bill both the E/M and the procedure separately — OPPS packaging rules govern payment, not Modifier 27. Correct Action: Remove Modifier 27. Report CPT 99213 and CPT 20610 on separate lines with no Modifier 27. The physician bills Modifier 25 on their CMS-1500. If the payer bundles the E/M into the injection under OPPS packaging, no modifier overrides this — it is a payment system design feature, not a billing error.

Scenario 4: Three Outpatient Encounters — Multiple Modifier 27 Applications

Patient: A complex oncology patient has three scheduled hospital-based outpatient visits in one day: a pre-chemotherapy lab review and exam in the infusion clinic (9:00 AM), a radiation oncology treatment planning consultation (11:30 AM), and a psycho-oncology mental health evaluation (2:00 PM) — all within the same hospital system and billed on one UB-04. E/M Codes: Line 1: CPT 99214 (Infusion clinic E/M) | Rev 0510 | No Modifier 27 Line 2: CPT 99243 (Consultation, radiation oncology) | Rev 0510 | Modifier 27 Line 3: CPT 90792 (Psychiatric evaluation) | Rev 0900 | Modifier 27 Coding Rationale: Three clinically distinct encounters, three separate departments, three separate notes. Modifier 27 is appended to each encounter after the first (Lines 2 and 3). Payer-specific policies may affect coverage of all three E/M services; pre-authorization verification is advisable for complex multi-encounter days in cancer care.