CPT 88355Laboratory

M/phmtrc alys skeletal musc

CPT 88355 covers computerized analysis of skeletal muscle tissue samples to measure specific characteristics like fiber size and distribution. This lab test helps diagnose muscle diseases and disorders by quantifying muscle tissue properties that can't be assessed by visual examination alone.

Showing rates for

National Average

Base Medicare rate

$137.80

This calculator gives a typical-case estimate using standard Medicare modifier rules. Actual payment depends on payer policies, documentation, code-specific CMS status indicators, and locality. Verify before billing.

RVU breakdown

Work RVU

1.85

PE RVU (NF)

2.38

MP RVU

0.03

Total RVU

4.26

Conversion factor: 32.3465 · Source: CMS MPFS RVU25A · Confidence: High

NCCI bundling edits

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Billing tips

Always bill 88355 in addition to the primary muscle biopsy pathology code (88302 or 88305), not as a standalone service
Impact: Prevents $137.80 denial for lack of medical necessity or missing primary service
Document the specific morphometric parameters measured (fiber diameter, fiber type ratio, etc.) and the quantitative method used in the pathology report
Impact: Reduces audit risk and supports medical necessity; missing quantitative data accounts for 35-40% of denials
Verify that actual morphometric analysis was performed, not just routine histochemical staining; coding 88355 for routine ATPase or oxidative enzyme stains without quantification is incorrect
Impact: Prevents upcoding allegations and potential $137.80 recoupment plus penalties
Check if your MAC or commercial payer has specific LCD/NCD requirements for morphometric analysis coverage, as some require pre-authorization for suspected diagnosis
Impact: Some MACs limit coverage to specific diagnoses; failing to verify can result in 100% denial
When splitting professional and technical components, ensure both billers use matching modifiers (26 and TC) and reference the same specimen
Impact: Mismatched modifiers can trigger duplicate payment audits and require $137.80 refund
Report 88355 only once per specimen regardless of how many different morphometric parameters are measured
Impact: Prevents overbilling denials; code is per specimen, not per parameter measured

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Frequently asked questions

What is the Medicare reimbursement rate for CPT 88355 in 2025?

The 2025 Medicare national average reimbursement for CPT 88355 is $137.80 for both facility and non-facility settings, based on 4.26 total RVUs and the 2025 conversion factor of $32.3465.

Can CPT 88355 be billed alone or does it require a primary pathology code?

CPT 88355 is an add-on code that should be billed in conjunction with the primary muscle biopsy pathology examination code (typically 88302 or 88305). It represents additional morphometric analysis beyond the routine pathologic examination and should not be billed as a standalone service.

What is the difference between CPT 88355 and routine muscle biopsy examination?

CPT 88355 represents specific quantitative morphometric analysis using computerized or manual measurement systems to generate numeric data about muscle fiber characteristics. Routine muscle biopsy examination includes qualitative histologic and histochemical assessment without the quantitative measurements that define morphometric analysis.

How many times can CPT 88355 be billed per muscle biopsy specimen?

CPT 88355 should be reported only once per specimen, regardless of how many different morphometric parameters are measured. Multiple measurements on the same specimen (fiber diameter, fiber type ratio, etc.) are included in the single code.

What documentation is required to support billing CPT 88355?

Documentation must include the specific morphometric parameters measured with actual numeric values, the quantitative methodology used, comparison to normal reference ranges, and clinical indication for the analysis. The pathology report must demonstrate that true quantitative analysis was performed, not just routine qualitative histochemical interpretation.

Which medical specialties typically bill CPT code 88355?

CPT 88355 is primarily billed by pathologists and neuropathologists, particularly those with expertise in neuromuscular pathology. The service is performed in hospital pathology departments, independent pathology laboratories, academic medical centers, and specialized neuromuscular diagnostic reference laboratories.

What are the most common denial reasons for CPT 88355?

The most common denials include lack of medical necessity documentation, insufficient evidence that quantitative morphometric analysis was actually performed versus routine assessment, bundling with the primary pathology code, and duplicate billing when multiple parameters are measured on the same specimen.