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Modifier XP

Definition

Modifier XP is used when two services are provided by different practitioners on the same day and are otherwise subject to NCCI bundling. The practitioners must be distinct individuals (not same person, not same group providing same service). Modifier XP tells the payer the services come from separate providers and should not be bundled.

When to Use

  1. Orthopedic surgeon performs knee repair (27447); physical therapist provides separate PT evaluation same day by different provider (97110-XP)
  2. Cardiologist orders stress test (93000); cardiac nurse performs test separately (93000-XP)
  3. Family medicine physician sees patient for cold (99213); nurse practitioner independently evaluates cardiac complaint (99213-XP same time slot different provider)
  4. Surgeon performs biopsy (11100); pathologist independently reviews specimen same day (88304-XP)

Documentation Requirements

Document both practitioners separately. Show each provider's independent medical decision-making and clinical involvement. Note provider names and credentials. Do not show one service as assistant to the other. Each practitioner should document independently in medical record. Time-based services should show each provider's time separately.

Payer-Specific Rules

Payer Acceptance Common Denials Notes
Medicare Accepted; NCCI override CO-102: Component parts NCCI allows XP. Different practitioners required; different groups acceptable.
Aetna Accepted; routine payment CO-4: Service bundled Prefer XP. Pay both if practitioners are different individuals.
United Healthcare Accepted; standard approval CO-59: Not separately payable Approve XP when practitioners documented. Lower scrutiny than 59.
Cigna Accepted with documentation CO-151: Documentation missing Will pay. Require both practitioners documented in chart.
Humana Accepted; good approval CO-3: Service not covered Routine approval of XP when providers are distinct.
  • 59 – Distinct procedural service. Use 59 only when XP does not apply.
  • XE – Separate encounter. Use if different time slots/encounters.
  • XS – Separate structure. Use if different body sites.
  • XU – Non-overlapping service. Use for unrelated services.

Common Denials

CARC Code Reason Primary Cause
CO-102 Component parts billed separately Payer sees second provider's service as component of first; does not recognize XP override.
CO-4 Service bundled in plan Payer contract bundles services regardless of separate providers.
CO-151 Documentation insufficient Claim lacks evidence of separate practitioners.

FAQ

Do the practitioners have to be from different specialties?

No. Two providers from same specialty can use XP if they are different individuals providing separate services.

Can an assistant surgeon use XP?

No. Assistant surgeon has specific modifiers (80, 81, 82). XP is for non-assistant separate services.

If both practitioners are from the same group, can I still use XP?

Yes. Group affiliation does not matter. Different individual practitioners qualifies for XP.

Prevent These Denials

Get multi-provider claims paid correctly. Use a co-pilot to ensure XP documentation.

Related Resources

This reference is current as of 2026-03-23. Payer policies change. Always verify against the payer's latest policy documentation.
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