CPT 84182Laboratory

Protein western blot test

CPT code 84182 covers a protein western blot test, a specialized laboratory technique that identifies specific proteins in a blood or tissue sample by separating them by size and detecting them with antibodies.

Showing rates for

National Average

Base Medicare rate

$17.14

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

0.37

PE RVU (NF)

0.15

MP RVU

0.01

Total RVU

0.53

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

NCCI bundling edits

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Billing tips

Link to specific ICD-10 codes that support medical necessity for western blot testing, particularly for Lyme disease confirmation (A69.2x codes) or autoimmune conditions
Impact: Prevents medical necessity denials which account for approximately 30-40% of laboratory test denials; ensures $17.14 reimbursement
Verify LCD (Local Coverage Determination) requirements for your MAC before performing test; many MACs require prior positive screening test results
Impact: Failure to meet LCD criteria results in 100% denial; documentation of prior ELISA or other screening test can be mandatory
Bill only once per protein target tested; if multiple proteins are analyzed, evaluate whether separate reporting is supported
Impact: Unbundling can trigger audits; proper unit reporting ensures accurate $17.14 per test reimbursement without overpayment risk
Document the specific protein(s) being detected in test requisition and results to support distinct testing when multiple codes are reported
Impact: Reduces bundling denials when western blot is performed alongside other immunoassays; maintains separate reimbursement streams
For Lyme disease testing, ensure compliance with CDC two-tier testing protocol and document tier-one positive results
Impact: Non-compliant testing order results in denial; proper protocol adherence maintains 0.53 RVU reimbursement
Submit claims with NPI of performing laboratory when using modifier 90 for reference laboratory testing
Impact: Incorrect NPI reporting causes payment delays or denials; proper attribution ensures timely $17.14 payment to correct entity

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Frequently asked questions

What is the Medicare reimbursement rate for CPT code 84182 in 2025?

The 2025 Medicare national average reimbursement rate for CPT 84182 is $17.14 for both facility and non-facility settings, based on a total RVU of 0.53 and conversion factor of 32.3465.

Does CPT 84182 require prior authorization for Medicare?

Prior authorization requirements vary by Medicare Administrative Contractor (MAC). Many MACs require documentation of a prior positive screening test, particularly for Lyme disease confirmation. Check your local LCD for specific prior authorization and medical necessity requirements.

How many units of 84182 can be billed per day?

Typically one unit per protein target analyzed. Multiple units on the same day require medical necessity documentation and may trigger review. Use modifier 91 for medically necessary repeat testing performed on the same day to obtain subsequent results.

What diagnosis codes support medical necessity for CPT 84182?

Common supporting diagnoses include Lyme disease screening positive results (A69.2x), autoimmune disorders (M35.x series), HIV testing confirmation (Z11.4, B20), and neurological conditions requiring protein analysis. Specific LCD requirements vary by MAC and should be verified before testing.

Can CPT 84182 be billed with an office visit on the same day?

Yes, laboratory tests like 84182 can be billed separately from office visits. The laboratory service does not require modifier 25 as it is a distinct service. However, ensure the office visit medical necessity is separately documented if billing both services.

What is the difference between CPT 84182 and 86617 for Lyme disease testing?

CPT 86617 is specific to Lyme disease antibody immunoblot (western blot), while 84182 is a general protein western blot code. For Lyme disease confirmation testing, 86617 is the more specific and appropriate code. Using 84182 for Lyme antibody testing may result in denials or requests for code correction.

Is CLIA certification required to bill CPT code 84182?

Yes, western blot testing requires CLIA certification with high-complexity testing approval. The laboratory must have appropriate CLIA certification, and personnel must meet qualifications for high-complexity testing. Billing without proper certification can result in denial and potential fraud investigation.