Double-Charge Detector 0434U

Rx metab advrs vrnt alys 25 — 332 bundling rules

If your bill lists 0434U alongside any of these codes as separate charges, it may be an unbundling error.

By David Park , Healthcare Cost Researcher · Published March 15, 2026 · Updated April 3, 2026

About the analyst

David Park researches procedure pricing and insurance reimbursement patterns at BillRazor Research. He specializes in cost comparison across care settings and metropolitan areas. Expertise: procedure pricing, insurance reimbursement, cost comparison.

NCCI edit data

332 code pairs

Updated 2026-04-03

Bundling rules — 0434U

NCCI edits: these codes have billing restrictions when billed with 0434U

Research suggests 49–80% of hospital bills contain errors. Our system checks every line item against Medicare benchmarks.

Common unbundling errors — medical procedures

Unbundling occurs when medical providers bill two separate codes for services that should be combined into a single charge according to National Correct Coding Initiative (NCCI) rules. In other procedures including anesthesia, radiology, pathology, and miscellaneous support services, common unbundling patterns include separately billing diagnostic imaging with its professional interpretation when both should be included in one comprehensive code, and charging for basic monitoring or preparation services alongside the primary procedure when these components are considered integral parts of the main service. Another frequent error involves billing multiple pathology examination codes for what constitutes a single comprehensive analysis. With 809 other codes subject to bundling restrictions in the NCCI database, these errors create charges above the benchmark for patients who receive multiple bills for what should constitute one complete service. The potential difference between unbundled billing and correct coding practices can significantly impact patient financial responsibility, as they may face duplicate charges for components of care that medical coding standards define as a single billable service.

What to check on your bill

When reviewing itemized bills for procedure bundling issues, patients should examine several key areas to identify potential billing irregularities. Look for multiple procedure codes billed on the same date that represent components of a comprehensive service, such as separate charges for incision, repair, and closure when these steps are typically included in one primary procedure code. Watch for code patterns where related procedures share the same first three digits, as these often indicate services that should be bundled together under Medicare's Correct Coding Initiative. Check for appropriate modifier usage, particularly modifier 59 or XS, which legitimately allow separate billing when procedures are performed on different anatomical sites or during distinct sessions. Without proper modifiers, separately billed related procedures may represent charges above the benchmark. Compare your itemized statement against standard bundling practices for your specific procedure type to identify potential differences in billing patterns.

All bundling rules for 0434U

332 code pairs that have billing restrictions with this procedure.

Never bill together

315

May bill with modifier

Code	Description	Rule
0029U	Rx metab advrs trgt seq alys	Never bill together
0030U	Rx metab warf trgt seq alys	Never bill together
0034U	Tpmt nudt15 genes	Never bill together
0070U	Cyp2d6 gen com&slct rar vrnt	Never bill together
0169U	Nudt15&tpmt gene com vrnt	Never bill together
0173U	Psyc gen alys panel 14 genes	May bill with modifier
0175U	Psyc gen alys panel 15 genes	May bill with modifier
0392U	Rx metab genrx ia 16 genes	Never bill together
36591	Draw blood off venous device	Never bill together
36592	Collect blood from picc	Never bill together
80503	Path clin consltj sf 5-20	May bill with modifier
80504	Path clin consltj mod 21-40	May bill with modifier
80505	Path clin consltj high 41-60	May bill with modifier
81105	Hpa-1 genotyping	May bill with modifier
81106	Hpa-2 genotyping	May bill with modifier
81107	Hpa-3 genotyping	May bill with modifier
81108	Hpa-4 genotyping	May bill with modifier
81109	Hpa-5 genotyping	May bill with modifier
81110	Hpa-6 genotyping	May bill with modifier
81111	Hpa-9 genotyping	May bill with modifier
81112	Hpa-15 genotyping	May bill with modifier
81120	Idh1 common variants	May bill with modifier
81121	Idh2 common variants	May bill with modifier
81161	Dmd dup/delet analysis	May bill with modifier
81162	Brca1&2 gen full seq dup/del	May bill with modifier
81163	Brca1&2 gene full seq alys	May bill with modifier
81164	Brca1&2 gen ful dup/del alys	May bill with modifier
81165	Brca1 gene full seq alys	May bill with modifier
81166	Brca1 gene full dup/del alys	May bill with modifier
81167	Brca2 gene full dup/del alys	May bill with modifier
81168	Ccnd1/igh translocation alys	May bill with modifier
81170	Abl1 gene	May bill with modifier
81171	Aff2 gen aly detc abnl allel	May bill with modifier
81172	Aff2 gen alys charac alleles	May bill with modifier
81173	Ar gene full gene sequence	May bill with modifier
81174	Ar gene known famil variant	May bill with modifier
81175	Asxl1 full gene sequence	May bill with modifier
81176	Asxl1 gene target seq alys	May bill with modifier
81177	Atn1 gene detc abnor alleles	May bill with modifier
81178	Atxn1 gene detc abnor allele	May bill with modifier
81179	Atxn2 gene detc abnor allele	May bill with modifier
81180	Atxn3 gene detc abnor allele	May bill with modifier
81181	Atxn7 gene detc abnor allele	May bill with modifier
81182	Atxn8os gen detc abnor allel	May bill with modifier
81183	Atxn10 gene detc abnor allel	May bill with modifier
81184	Cacna1a gen detc abnor allel	May bill with modifier
81185	Cacna1a gene full gene seq	May bill with modifier
81186	Cacna1a gen known famil vrnt	May bill with modifier
81187	Cnbp gene detc abnor allele	May bill with modifier
81188	Cstb gene detc abnor allele	May bill with modifier

Showing 50 of 332 rules. Show all

FAQ — medical procedure bundling

What is NCCI bundling and what does 'bundled' mean on a medical bill?

NCCI bundling refers to the National Correct Coding Initiative rules that prevent certain procedure codes from being billed separately when performed together. When codes are bundled, one procedure is considered inclusive of another, meaning only the primary procedure should be billed rather than charging for each component separately.

How can I identify if codes were incorrectly unbundled on my bill?

Incorrectly unbundled codes appear as separate line items on your bill when NCCI rules indicate they should be grouped together under one primary procedure code. This typically occurs with anesthesia, radiology, pathology, and miscellaneous support services that are considered integral to the main procedure being performed.

What should I do if I find unbundled charges on my medical bill?

Contact your healthcare provider's billing department to request a review of the charges and provide documentation showing the NCCI bundling rules that apply. Request an itemized explanation of why the codes were billed separately and ask for a corrected bill that reflects proper bundling if no valid modifier justification exists.

When is it legitimate to use modifiers to override NCCI bundling rules?

Modifiers are appropriately used when procedures are performed on different anatomical sites, during separate patient encounters, or when distinct procedural services are provided that don't fall under the bundling restrictions. The modifier usage must be supported by clear documentation in the medical record that demonstrates the services were truly separate and distinct from the bundled procedure.

Rates shown are from the 2026 Medicare Physician Fee Schedule and CMS IPPS. BillRazor compares your bill against these data sources. See how it works →

Data source: CMS National Correct Coding Initiative (NCCI) Procedure-to-Procedure (PTP) edits, updated quarterly. These code pairs are maintained by CMS to prevent improper billing of services that should be billed as a single procedure.

What this means: When two codes are listed as an NCCI edit pair, billing them separately on the same date of service is typically incorrect. "Never bill together" means no modifier can override the rule. "May bill with modifier" means the codes can be billed separately with appropriate documentation.