Xolair (omalizumab) — HCPCS J2357

The 5 mg unit basis — biller error trap CMS HCPCS verified May 2026

The single most important fact about billing Xolair: 1 unit = 5 mg, not 1 mg.

Most specialty injectable HCPCS codes use 1 mg = 1 unit. Xolair is a notable exception: J2357 is defined as "Injection, omalizumab, 5 mg." Reporting milligrams as units (e.g., billing 150 units for a 150 mg dose) inflates the claim by 5× and is a top cause of Xolair denials and post-payment recoupments.

Four FDA-approved indications FDA label verified Apr 2026

Each indication has its own dosing algorithm, ICD-10 family, and payer-policy logic. Get the indication right or the PA fails.

Food allergy indication — FDA approved February 2024 NEW indication

First-ever biologic FDA-approved for IgE-mediated food allergy. Major SEO + payer-policy implications.

On February 16, 2024, the FDA approved Xolair for reduction of allergic reactions (Type I hypersensitivity, including anaphylaxis) that may occur with accidental exposure to one or more foods, in adults and pediatric patients aged 1 year and older with IgE-mediated food allergy. This was the first biologic medication approved in the US for this indication.

Critical clinical caveats (must be documented for PA)

• NOT a substitute for food avoidance. Patients must continue strict avoidance.
• NOT for emergency treatment of allergic reactions (epinephrine remains the standard).
• Dosing follows an IgE + weight table (similar to asthma); range is 75 mg q4wk to 600 mg q2wk.
• Pivotal trial: OUtMATCH (NIAID-sponsored) — demonstrated reduction of severity of allergic reaction during food challenge.

Payer policy state (May 2026 — still evolving)

• Most major commercial plans (UHC, Aetna, BCBS) now have food-allergy-specific PA criteria, but criteria vary widely.
• Common requirements: documented IgE-mediated food allergy by allergist, prior severe reaction(s) including anaphylaxis, multiple-food sensitization, baseline serum IgE level, body weight.
• Some payers require oral food challenge documentation; others accept skin prick or specific IgE testing.
• Medicare Part B coverage applies in physician-office settings; Part D pathway exists for self-administration after first 3 doses.

Dosing — asthma, CRSwNP, food allergy (IgE + weight) FDA label Feb 2024

From FDA prescribing information, label revised February 2024 (BLA 103976).

The IgE + weight calculator

Dose and frequency for asthma, CRSwNP, and food allergy are determined by looking up the patient's baseline total serum IgE level (IU/mL) and body weight (kg) in the FDA dosing tables. The result is a dose between 75 mg and 600 mg, given every 2 or every 4 weeks. Doses > 150 mg per injection require multiple injection sites.

Worked example — adult allergic asthma

Dosing — chronic spontaneous urticaria (fixed) FDA label Apr 2026

CSU is the only Xolair indication that does NOT use IgE+weight dosing.

• 150 mg or 300 mg SC every 4 weeks — fixed dose
• NOT based on IgE level or body weight
• No baseline IgE testing required
• Most patients start at 300 mg q4wk; 150 mg may be considered
• Reassess periodically for continued need

Worked example — CSU

IgE biomarker testing — required for asthma / CRSwNP / food allergy CPT verified May 2026

Bill IgE testing on a separate claim line. Get the result in hand BEFORE submitting Xolair PA.

NDC reference FDA NDC Directory verified May 2026

Administration codes — SC therapeutic injection CPT verified May 2026

Xolair is subcutaneous. The correct CPT is 96372. Wrong-route admin codes are a top denial source.

Self-administration after first 3 in-clinic doses FDA label Feb 2024

Xolair has both an HCP-administered pathway (medical benefit) and a self-administered pathway (medical/Part B or Part D).

Per the Xolair label, the first 3 doses must be administered by a healthcare professional in a setting equipped to manage anaphylaxis, with appropriate post-injection observation (typically 2 hours for the first 3 doses, 30 minutes thereafter when administered by HCP). After the first 3 doses, suitable adult patients and caregivers of pediatric patients may be trained to self-administer Xolair at home with the prefilled autoinjector.

Billing pathway differs by setting

Anaphylaxis — FDA Boxed Warning FDA label Feb 2024

Operational requirements

• First 3 doses must be administered by an HCP in a setting equipped to manage anaphylaxis
• Observation period after each HCP-administered dose (per label and protocol; common practice is 2 hours for first 3 doses, then 30 minutes)
• Injectable epinephrine (auto-injector) on-hand in the administration setting
• Patient wallet card recommended with instructions for emergency presentation
• Patients trained for home self-administration must be re-trained on anaphylaxis recognition + epinephrine use; prescribe an auto-injector

Modifiers CMS verified May 2026

JZ — required on virtually every Xolair claim

Effective July 1, 2023, CMS requires the JZ modifier on all single-dose container claims when no drug is discarded. Xolair PFS and autoinjector are single-dose single-use devices delivered at the labeled dose — for all standard doses (75, 150, 225, 300, 375, 450, 600 mg), no waste occurs. JZ applies to virtually every Xolair claim.

JW — very rare for Xolair

JW reports the discarded portion of a single-dose vial. For Xolair, JW only applies if a partial PFS or autoinjector dose is administered with documented waste — an unusual scenario because Xolair doses are computed in 75 mg increments matching the available device sizes.

Modifier 25 — same-day E/M

Use modifier 25 on the E/M code when a significant, separately identifiable evaluation and management service is performed on the same day as the injection. Routine pre-injection clinical assessment is bundled.

340B modifiers (JG, TB)

For 340B-acquired Xolair, follow your MAC's current 340B modifier policy. Verify the 340B sub-ceiling pricing through your covered-entity portal; Genentech 340B pricing is generally offered at low single-digit dollars per 5 mg unit.

ICD-10-CM by indication FY2026 verified May 2026

Multi-indication: pick the family that matches the documented indication. Mismatches trigger PA failure.

Site of care & place of service Verified May 2026

Because Xolair is SC and (after dose 3) self-administrable, site-of-care policy for Xolair is more permissive than for IV biologics. Major payers prefer office or home administration over hospital outpatient department (HOPD).

Claim form field mapping Genentech Access verified 2025

From Genentech Access Solutions Xolair coding & billing guide.

Payer policy snapshot + step therapy Reviewed May 2026

All major payers PA Xolair. Step therapy and indication-specific documentation requirements vary.

Step therapy detail

• Asthma: Most payers require failure of ICS+LABA combination therapy at adequate dose for ≥3 months before approving Xolair. Documentation: prescribed regimen, adherence, exacerbation/symptom data.
• CSU: Most payers require H1-antihistamine failure (4× standard dose for ≥1–2 weeks per AAAAI guidelines). Some require leukotriene receptor antagonist trial as well.
• CRSwNP: Failure of nasal corticosteroid + (for some payers) prior surgical intervention or saline irrigation.
• Food allergy (NEW 2024): No clear "step" therapy because there is no prior pharmacologic option. Payers focus on severity-of-disease documentation: allergist diagnosis, prior anaphylaxis, multi-food sensitization, body weight, baseline IgE.

Medicare reimbursement CMS Q2 2026 (live)

Quarterly ASP from CMS Part B Drug Pricing File. Refreshes automatically each quarter.

Coverage

No NCD specific to omalizumab. Coverage falls under MAC LCDs for biologics + the generic drug-coverage framework. All MACs cover J2357 for FDA-approved on-label indications with appropriate ICD-10 and (where required) IgE documentation. After the first 3 doses, Part D / pharmacy benefit pathway is common for self-administered home maintenance.

Code history

• J2357 — permanent code, effective January 1, 2005 (initial FDA approval was June 2003 as Xolair lyophilized vial; PFS launched later).
• The "5 mg per unit" basis has been unchanged since the code was created.

Patient assistance — Genentech Access Solutions Genentech verified May 2026

• Genentech Access Solutions (Xolair): 1-866-422-2377 / xolair.com/hcp/access-and-support — benefits investigation, prior authorization assistance, appeal support, alternate funding
• Xolair Co-pay Card: commercial copay support; eligible commercially-insured patients pay as little as $0 for the first dose and a reduced copay on subsequent doses (excludes Medicare, Medicaid, federal program patients)
• Genentech Patient Foundation: free Xolair for uninsured / underinsured patients meeting income requirements
• Foundations (for Medicare patients): refer to PAN Foundation, HealthWell Foundation, GoodDays/CDF — verify open allergic disease / asthma / urticaria / nasal polyps / food allergy funds quarterly
• Web: xolair.com/hcp/access-and-support

Common denials & how to fix them

Frequently asked questions

What is the HCPCS code for Xolair?

Xolair (omalizumab) is billed under HCPCS J2357 — "Injection, omalizumab, 5 mg." Each 5 mg equals one billable unit. This is one of the most common biller error traps for Xolair: a 150 mg dose is 30 units, not 150 units; a 300 mg dose is 60 units, not 300 units. J2357 has been the permanent code since January 1, 2005.

How many units do I bill for a 300 mg Xolair dose?

Bill 60 units of J2357 for a 300 mg Xolair dose (300 mg ÷ 5 mg/unit = 60 units). For a 150 mg dose, bill 30 units. For a 75 mg dose, bill 15 units. Reporting milligrams as units inflates the claim 5× and triggers automatic denial or payer recoupment.

What administration CPT do I use for Xolair?

CPT 96372 — "Therapeutic, prophylactic, or diagnostic injection; subcutaneous or intramuscular." Xolair is administered subcutaneously, NOT intravenously. Do NOT bill 96365 / 96366 (therapeutic IV) and do NOT bill 96413 / 96415 (chemo IV) — those will be denied. After the patient completes the first 3 in-clinic doses with observation and is approved for self-administration with the autoinjector, no admin CPT is billed.

Does Xolair have a boxed warning?

Yes. Xolair carries an FDA Boxed Warning for anaphylaxis. Anaphylaxis has been reported in approximately 0.2% of patients. Healthcare professional administration with an observation period is required for the first 3 doses. After the first 3 doses, suitable patients may self-administer at home with a Xolair autoinjector following appropriate training. A Xolair patient wallet card is recommended. Ensure injectable epinephrine is available in any setting where Xolair is administered.

What are the indications for Xolair?

Xolair is FDA-approved for: (1) Moderate-to-severe persistent allergic asthma (≥6 years); (2) Chronic spontaneous urticaria (CSU, ≥12 years, refractory to H1 antihistamines); (3) Chronic rhinosinusitis with nasal polyps (CRSwNP, ≥18 years); (4) IgE-mediated food allergy (≥1 year, FDA-approved February 2024) for reduction of allergic reactions with accidental exposure. Xolair is NOT a substitute for food avoidance.

Is total serum IgE testing required before starting Xolair?

Yes for asthma, CRSwNP, and food allergy — baseline total serum IgE level (CPT 82785) is required because dose and frequency are calculated from IgE level + body weight. The Xolair dosing tables apply for asthma when baseline IgE is between 30 and 1500 IU/mL. CSU does NOT require IgE testing — CSU dosing is fixed at 150 mg or 300 mg q4wk regardless of IgE level.

What is the Medicare reimbursement for J2357?

For Q2 2026, the Medicare Part B payment limit for J2357 is $41.823 per 5 mg unit (ASP + 6%) — equivalent to about $8.36 per mg. A 150 mg dose reimburses at approximately $1,254.69 per administration; a 300 mg dose at approximately $2,509.38. Annualized cost (Medicare ASP+6%) for 300 mg q4wk: approximately $32,621/year. Sequestration (~2%) reduces actual paid to roughly ASP + 4.3%.

How is the food allergy indication billed differently?

The food allergy indication (FDA-approved February 2024) uses the same J2357 HCPCS, the same IgE+weight dose calculator as asthma, the same SC route, and the same CPT 96372 admin code. Differences are clinical-documentation: ICD-10 uses Z91.01x (food allergy status by food) plus T78.0x–T78.4x (anaphylaxis / allergy reaction codes); payer policies are still evolving; many payers require allergist documentation and prior severe reaction history. The first 3 doses must be HCP-administered with observation regardless of indication.

Source documents

1. DailyMed — XOLAIR (omalizumab) Prescribing Information
   FDA-approved label, most recently revised February 2024 (food allergy indication added; BLA 103976)
2. FDA Press Announcement — First medication to help reduce allergic reactions to multiple foods after accidental exposure (February 16, 2024)
3. Genentech Access Solutions — Xolair Coding & Coverage HCP page
   Document footers: Genentech Access Solutions Xolair Billing Guide, 2025
4. CMS — Medicare Part B Drug ASP Pricing File
   Q2 2026 quarterly file, effective April 1 – June 30, 2026
5. SEER CanMED — HCPCS J2357 reference
6. UnitedHealthcare — Medical Benefit Drug Policy: Omalizumab (Xolair)
7. Aetna CPB 0314 — Asthma (covers omalizumab)
8. Aetna CPB 0732 — Urticaria (covers omalizumab CSU)
9. GINA — Global Initiative for Asthma 2025 Report (anti-IgE biologics)
10. AAAAI — CSU + food allergy biologics guidance
11. FDA National Drug Code Directory

About this page

We maintain this page as a living reference. Medicare ASP pricing is bound to our underlying CareCost data layer and refreshes automatically when CMS publishes new quarterly files. Coding and policy content is reviewed at least quarterly and updated whenever a source document changes.

Found an error? Email hello@carecostestimate.com.

Refresh cadence

Reviewer

Change log

• May 2, 2026 — Initial publication. ASP data: Q2 2026. Manufacturer source: Genentech Access Solutions Xolair Billing Guide 2025. FDA label: Feb 2024 revision adding food allergy indication (BLA 103976). 4 indications: allergic asthma, CSU, CRSwNP, IgE-mediated food allergy (NEW Feb 2024). Anti-IL-5 cousins (Nucala, Cinqair, Fasenra) cross-linked.

Methodology

Every claim on this page is sourced inline. Pricing reflects the current CMS Part B Drug ASP Pricing File. Payer policies are read directly from each payer's published medical/pharmacy policy documents. Indication list and dosing tables are verified against the current FDA label revision. We do not paraphrase from billing-software vendor blogs.