Heart flow reserve measure
CPT 93571 covers the measurement of coronary flow reserve during a cardiac catheterization procedure. This test evaluates how well blood flows through the heart's arteries when the heart is stressed versus at rest.
RVU breakdown
Conversion factor: 32.3465 · Source: CMS MPFS RVU25A · Confidence: High
Billing tips
Always bill 93571 as an add-on code with primary catheterization codes (93454, 93455, 93456, 93457, 93458, 93459, 93460, 93461) - never as standalone
Impact: Prevents 100% denial; 93571 is designated add-on code (+) and will auto-deny without appropriate primary procedure
Document both baseline and hyperemic flow velocity measurements with adenosine dosing protocol and timing in procedure report
Impact: Reduces denial rate by approximately 40-60% during medical necessity audits; ensures payment of full $68.25
Bill one unit of 93571 per vessel assessed, not per injection or measurement attempt - most payers limit to 2-3 vessels per session
Impact: Maximum reimbursement of $136.50-$204.75 when assessing multiple vessels; overbilling risks recoupment of all units
Verify payer-specific coverage policies as some Medicare MACs and commercial payers require prior authorization for CFR measurements
Impact: Prevents delayed or denied payment; some contractors have LCD restrictions limiting coverage to specific clinical scenarios
Use diagnosis codes documenting intermediate stenosis (I25.1x codes) or microvascular disease rather than generic chest pain for higher approval rates
Impact: Increases first-pass approval rate by 25-35%; supports medical necessity for functional assessment
Time and date-stamp all hemodynamic measurements in catheterization report to demonstrate real-time assessment during primary procedure
Impact: Protects $68.25 reimbursement during post-payment audits; timestamps prove measurements were performed, not added retrospectively
Common denials
Billed without appropriate primary cardiac catheterization procedure code
How to appeal: Resubmit claim with correct primary procedure code (93454-93461 series) and 93571 as add-on. Include operative report showing both catheterization and flow reserve measurement. Reference CPT manual designation of 93571 as add-on code requiring primary procedure.
Medical necessity denial - flow reserve measurement not justified for documented coronary anatomy
How to appeal: Submit catheterization images showing intermediate stenosis (40-70% range) with documentation explaining why anatomic assessment alone was insufficient. Include references to ACC/AHA appropriateness criteria supporting functional assessment for intermediate lesions. Provide hyperemic and baseline flow velocity data demonstrating completed measurement.
Duplicate service denial when billing multiple vessels on same date
How to appeal: Resubmit with modifier 59 on second and subsequent units. Provide itemized documentation showing separate measurements in distinct coronary vessels (LAD, LCX, RCA). Include anatomic diagrams or images identifying each measured vessel with corresponding flow data.
Bundling denial with other hemodynamic measurements or pressure wire assessments (93571 vs 93572)
How to appeal: Clarify specific measurement performed: 93571 is flow reserve (velocity-based), while 93572 is FFR (pressure-based). Submit catheterization report highlighting flow velocity tracings and adenosine administration protocol. If both were performed, document separate clinical indications for each measurement type.
Frequently asked questions
What is the Medicare reimbursement rate for CPT code 93571 in 2025?
The 2025 Medicare national average payment for CPT 93571 is $68.25 for both facility and non-facility settings. This rate is based on 2.11 total RVUs multiplied by the 2025 conversion factor of 32.3465. Actual payment may vary based on geographic locality adjustments.
Can CPT 93571 be billed alone or does it require another procedure code?
CPT 93571 is an add-on code (designated with + symbol) and cannot be billed alone. It must be reported with a primary cardiac catheterization procedure code from the 93454-93461 series. Billing 93571 without an appropriate primary code will result in automatic denial.
How many times can you bill 93571 in one catheterization session?
You can typically bill 93571 once per coronary vessel assessed, with most payers allowing 2-3 units per session when medical necessity is documented. Each unit represents a separate coronary flow reserve measurement in a distinct vessel. Documentation must clearly identify each vessel measured with corresponding flow data.
What is the difference between CPT 93571 and 93572?
CPT 93571 measures coronary flow reserve (CFR) using flow velocity measurements, while CPT 93572 measures fractional flow reserve (FFR) using pressure measurements. CFR assesses velocity changes with vasodilation; FFR assesses pressure gradients across stenoses. These are distinct physiologic measurements and may both be performed in some cases with separate documentation.
What diagnosis codes support medical necessity for CPT 93571?
Diagnosis codes supporting 93571 include I25.10-I25.119 (atherosclerotic heart disease with intermediate stenosis), I20.0-I20.9 (angina pectoris), I25.83 (coronary microvascular dysfunction), and vessel-specific atherosclerosis codes. Documentation should show intermediate stenosis (40-70%) or suspected microvascular disease where functional assessment impacts treatment decisions.
Do I need modifier 26 when billing CPT 93571 in a hospital setting?
Modifier 26 is typically not necessary for 93571 as both facility and non-facility rates are identical at $68.25, indicating no practice expense differential. The cardiologist performing and interpreting the measurement bills the complete code. However, verify individual payer requirements as some may have specific billing protocols.
What documentation is needed to prevent denials for CPT 93571?
Required documentation includes baseline and hyperemic flow velocity measurements (with numeric values), calculated CFR ratio, vasodilator agent and dose, vessel(s) assessed, clinical indication for functional assessment, and how results influenced treatment decisions. Timestamped measurements in the catheterization report demonstrating real-time assessment are essential for audit protection.