CPT 86335Laboratory

Immunfix e-phorsis/urine/csf

CPT code 86335 covers immunofixation electrophoresis testing performed on urine or cerebrospinal fluid (CSF) samples to detect and identify abnormal proteins, particularly monoclonal immunoglobulins that may indicate conditions like multiple myeloma or other plasma cell disorders.

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

Clearly document specimen source (urine vs CSF) in test requisition and results report, as 86335 specifically covers urine/CSF while 86334 covers serum
Impact: Prevents 15-20% of denials related to incorrect code selection and ensures proper differentiation from serum immunofixation
Verify medical necessity with appropriate diagnosis codes such as D89.1 (cryoglobulinemia), C90.00 (multiple myeloma), or R80.9 (proteinuria unspecified) before performing test
Impact: Reduces denial rate by approximately 25% and ensures LCD/NCD compliance for Medicare coverage
Do not bill 86335 on the same day as 86334 for the same patient unless specimens are from different sources and medical necessity is clearly documented
Impact: Prevents bundling denials and potential fraud allegations; use modifier 59/XU when legitimately billing both codes
For 24-hour urine collections, ensure collection methodology and adequacy are documented to support test validity
Impact: Strengthens medical necessity documentation and reduces audit vulnerability by 30-40%
Bill 86335 separately from routine urinalysis or CSF protein tests; these are distinct procedures not subject to bundling
Impact: Ensures receipt of full $17.14 Medicare reimbursement without inappropriate reductions
When sending specimens to reference laboratories, verify that the reference lab will bill directly or provide appropriate documentation for you to bill with modifier 90
Impact: Prevents duplicate billing issues and clarifies financial responsibility, avoiding payment delays

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Frequently asked questions

What is the Medicare reimbursement rate for CPT code 86335 in 2025?

The 2025 Medicare national average reimbursement rate for CPT 86335 is $17.14 for both facility and non-facility settings. This rate is based on 0.53 total RVUs multiplied by the 2025 conversion factor of 32.3465. Actual reimbursement may vary by geographic locality based on the GPCI adjustment factors.

What is the difference between CPT code 86334 and 86335?

CPT 86334 covers immunofixation electrophoresis performed on serum specimens, while CPT 86335 is specifically for immunofixation performed on urine or cerebrospinal fluid (CSF) specimens. The specimen source determines which code to use. Both tests use similar methodology but require different codes based on the biological sample being analyzed. Using the wrong code based on specimen type is a common denial reason.

How many RVUs is CPT code 86335 worth?

CPT code 86335 has a total RVU value of 0.53, consisting of 0.37 work RVUs, 0.15 practice expense RVUs (both facility and non-facility), and 0.01 malpractice RVUs. These are the official 2025 values from the CMS Medicare Physician Fee Schedule.

What diagnosis codes support medical necessity for CPT 86335?

Common diagnosis codes supporting CPT 86335 include C90.00 (multiple myeloma), D89.1 (cryoglobulinemia), R80.9 (proteinuria unspecified), E85.9 (amyloidosis), C90.10 (plasma cell leukemia), and R77.8 (other specified abnormalities of plasma proteins). The specific ICD-10 code should match the clinical indication, such as monitoring known disease or investigating unexplained protein abnormalities in urine or CSF.

Can CPT 86335 and 86334 be billed together on the same date of service?

Yes, CPT 86335 and 86334 can be billed together if performed on different specimen types (such as serum and urine) and medical necessity is documented for each test. Use modifier 59 or XU on the secondary code to indicate distinct procedural services. However, clear documentation must support why both specimen types required immunofixation analysis on the same date.

Is prior authorization required for CPT code 86335?

Prior authorization requirements for CPT 86335 vary by payer and specific plan. Most Medicare Administrative Contractors (MACs) do not require prior authorization for this laboratory test, but some Medicare Advantage plans and commercial insurers may require it, especially for repeat testing. Always verify authorization requirements with the specific payer before performing the test to avoid denial.

What modifier should I use when immunofixation electrophoresis needs to be repeated on the same day?

Use modifier 91 (repeat clinical diagnostic laboratory test) when CPT 86335 must be performed multiple times on the same day to obtain subsequent reportable results due to clinical necessity. This is different from modifier 76 (repeat procedure by same physician). Modifier 91 is specifically designed for laboratory tests and requires documentation explaining why the repeat test was medically necessary rather than being a duplicate or confirmation of an initial result.