CPT 88348Laboratory

Electron microscopy dx

CPT code 88348 covers diagnostic electron microscopy, a highly specialized laboratory test that uses an electron microscope to examine tissue samples at extremely high magnification to identify diseases that cannot be diagnosed with standard microscopy.

Showing rates for

National Average

Base Medicare rate

$477.43

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

1.51

PE RVU (NF)

13.12

MP RVU

0.13

Total RVU

14.76

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

NCCI bundling edits

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Billing tips

Document the specific clinical indication and why conventional light microscopy was inadequate before ordering electron microscopy
Impact: Reduces denial risk by 60-70%; lack of medical necessity is the top denial reason for this $477.43 procedure
Bill 88348 only once per specimen regardless of how many EM grids or blocks are examined; multiple areas of the same specimen are included
Impact: Prevents overbilling audits and recoupment; each specimen qualifies separately with modifier 59
Separate professional (26) and technical (TC) components when pathologist and laboratory are at different facilities
Impact: Ensures proper payment distribution; combined rate is $477.43, split appropriately between entities
Link to highly specific ICD-10 codes such as nephrotic syndrome types, specific storage diseases, or tumor morphology codes
Impact: Improves first-pass claim acceptance rate by 45-50% versus generic codes
Maintain detailed specimen preparation logs, imaging parameters, and photomicrographs as permanent documentation
Impact: Critical for audit defense; electron microscopy has high audit risk due to high RVU value of 14.76
Do not bill 88348 with routine surgical pathology codes 88302-88309 on same specimen without clear documentation of separate medical necessity
Impact: Prevents bundling denials and potential fraud flags; use modifier 59 only when truly distinct

Common denials

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Frequently asked questions

What is the Medicare reimbursement rate for CPT 88348 in 2025?

The 2025 Medicare national average payment for CPT 88348 is $477.43 for both facility and non-facility settings. This rate is based on a total RVU of 14.76 multiplied by the 2025 conversion factor of 32.3465.

When is electron microscopy CPT 88348 medically necessary?

CPT 88348 is medically necessary when light microscopy and routine immunohistochemistry cannot establish a definitive diagnosis. Common indications include kidney biopsies for glomerular disease classification, unusual tumor diagnosis, metabolic storage diseases, ciliary dysfunction evaluation, and identification of viral inclusions or unusual infectious organisms.

Can CPT 88348 be billed with surgical pathology codes?

Yes, but with caution. CPT 88348 can be billed separately from surgical pathology codes 88302-88309 when electron microscopy represents a distinct diagnostic service with separate medical necessity. Use modifier 59 to indicate a distinct procedural service and ensure documentation clearly supports the need for both examinations.

How many RVUs is CPT code 88348 worth?

CPT 88348 has a total RVU value of 14.76, consisting of 1.51 work RVUs, 13.12 practice expense RVUs, and 0.13 malpractice RVUs. The high PE RVU reflects the expensive electron microscopy equipment and specialized technical expertise required.

What is the difference between CPT 88348 and 88349?

CPT 88348 is for diagnostic electron microscopy used to establish a clinical diagnosis, while CPT 88349 is for scanning electron microscopy, which provides three-dimensional surface imaging rather than internal ultrastructural detail. 88348 is far more commonly used in clinical practice for diagnostic purposes.

Who can bill CPT 88348 - only pathologists?

CPT 88348 must be performed and interpreted by a board-certified pathologist with electron microscopy expertise. The code can be billed by the pathologist, hospital, or reference laboratory performing the service. When billed separately, use modifier 26 for professional component (interpretation) and TC for technical component (equipment and technical staff).

What documentation is required to bill CPT 88348 without denial?

Required documentation includes: physician order specifying electron microscopy, clinical indication showing why light microscopy was insufficient, detailed pathologist interpretation report with ultrastructural findings, specimen identification, correlation with clinical diagnosis, pathologist signature and credentials, and technical preparation records. Medical necessity justification is critical to avoid denials.