HCPCS
J0584
1 mg = 1 unit
Phase 1
Identify what you're billing
Confirm indication, weight-based dose, and washout of contraindicated meds before billing.
About Crysvita FDA verified May 2026
First-in-class anti-FGF23 monoclonal antibody. Co-developed by Ultragenyx + Kyowa Kirin.
Crysvita (burosumab-twza) is a fully human IgG1 monoclonal antibody that binds and inhibits fibroblast growth factor 23 (FGF23). FGF23 elevation is the underlying driver of phosphate wasting in X-linked hypophosphatemia (XLH) and tumor-induced osteomalacia (TIO). By neutralizing excess FGF23, Crysvita restores renal phosphate reabsorption and 1,25-dihydroxy vitamin D production, normalizing serum phosphate and improving bone mineralization.
Crysvita was FDA-approved April 17, 2018 (BLA 761068) for XLH in adults and pediatric patients ≥1 year. Pediatric expansion to ≥6 months followed in 2018. The TIO indication was added June 2020 for adults and pediatric ≥2 years when the underlying tumor cannot be curatively resected or located. Co-developed by Ultragenyx Pharmaceutical (US commercial rights) and Kyowa Kirin (rest-of-world rights).
XLH vs TIO — indication-specific dosing & criteria FDA label verified May 2026
Same drug, very different dosing schedules and PA criteria. Confirm the indication on the order before scheduling.
| X-linked hypophosphatemia (XLH) | Tumor-induced osteomalacia (TIO) | |
|---|---|---|
| Patient population | Adults + pediatric ≥6 months | Adults + pediatric ≥2 years (TIO is rare in pediatrics) |
| Underlying cause | PHEX gene mutation → constitutive FGF23 elevation (genetic, lifelong) | FGF23-secreting mesenchymal tumor (acquired, often paraneoplastic) |
| Pediatric dose | Start 0.8 mg/kg SC every 2 weeks, titrate to max 2 mg/kg, max 90 mg | 0.5 mg/kg SC every 4 weeks, titrate based on response, max 2 mg/kg / 90 mg |
| Adult dose | 1 mg/kg SC every 4 weeks, rounded to nearest 10 mg, max 90 mg | 0.5 mg/kg SC every 2 weeks, titrate based on response, max 2 mg/kg / 90 mg |
| Therapy duration | Lifelong — XLH is genetic, no cure | Until tumor is resected (then discontinue) OR lifelong if unresectable |
| Primary ICD-10 | E83.31 familial hypophosphatemia | D48.0 neoplasm of uncertain behavior of bone, OR D49.81 neoplasm of unspecified behavior of connective tissue |
| Genetic testing required | PHEX gene mutation OR family history with biochemistry | FGF23 elevation + tumor identified (imaging, octreotide scan, gallium-68 DOTATATE PET) OR cryptic tumor with FGF23 elevation |
| FDA approval date | April 17, 2018 (initial); pediatric ≥6 mo expansion 2018 | June 18, 2020 |
Key XLH/hypophosphatemia treatment landscape: Crysvita is the only disease-modifying
therapy. Conventional therapy = oral phosphate + active vitamin D (calcitriol). Crysvita has displaced
conventional therapy as 1L for moderate-severe XLH due to better efficacy on skeletal outcomes (Healing of
Rickets Score, HMP). Many adult patients still on legacy conventional therapy will switch to Crysvita
— document discontinuation of oral phosphate and calcitriol ≥1 week before first Crysvita dose.
TIO billing nuance: TIO patients often require a workup CPT code package (PET-CT, octreotide
scan, or gallium-68 DOTATATE imaging) BEFORE Crysvita PA submission. PA reviewers expect documentation of
either localized tumor (with reason for not resecting) or cryptic tumor (after appropriate imaging workup).
Dosing & unit math FDA label verified May 2026
Weight-based dosing with fixed 10/20/30 mg/mL vial sizes. Expect partial-vial waste — document with JW.
XLH adult (1 mg/kg q4wk, rounded to nearest 10 mg, max 90 mg)
- 40 kg patient → 40 mg dose → 40 units
- 55 kg patient → 55 mg → round to 60 mg → 60 units (uses 30+30 mg vials, 5 mg waste in calculated dose only)
- 70 kg patient → 70 mg → 70 units
- 90+ kg patient → capped at 90 mg max → 90 units (uses 30+30+30 mg vials)
- Frequency: every 4 weeks (~13 doses/year)
XLH pediatric (start 0.8 mg/kg q2wk, titrate to max 2 mg/kg, max 90 mg per dose)
- 20 kg patient → start 16 mg q2wk → 16 units (use 20 mg vial, 4 mg waste → JW for 4 units)
- 30 kg patient → start 24 mg q2wk → 24 units (use 30 mg vial, 6 mg waste → JW for 6 units)
- Titrate based on serum phosphate measured q4wk — can reach 2 mg/kg per dose
- Frequency: every 2 weeks (~26 doses/year)
TIO (0.5 mg/kg q4wk pediatric / q2wk adult, titrate based on response)
- 70 kg adult → 35 mg q2wk → 35 units (use 30+10 mg vials = 40 mg, 5 mg waste → JW)
- 20 kg pediatric → 10 mg q4wk → 10 units (use 10 mg vial, no waste → JZ)
- Titrate up to 2 mg/kg / 90 mg per dose based on serum phosphate response
Worked example — first-year billing for a 60 kg adult XLH patient (1 mg/kg q4wk)
# Single-dose calculation
Weight: 60 kg → dose: 60 mg (no rounding needed)
Vials used: 30 mg + 30 mg (no waste → JZ)
Drug units billed per dose: 60 (J0584)
HCPCS: J0584 · Modifier: JZ · Admin: 96372 (therapeutic SC)
# Year-1 totals
Total doses: 13 (every 4 weeks × 52 weeks)
Total drug units billed: 780 (13 × 60)
Total drug cost (Q2 2026 ASP+6%): ~$388,998 before sequestration
After ~2% sequestration: ~$381,218 actual paid
Weight: 60 kg → dose: 60 mg (no rounding needed)
Vials used: 30 mg + 30 mg (no waste → JZ)
Drug units billed per dose: 60 (J0584)
HCPCS: J0584 · Modifier: JZ · Admin: 96372 (therapeutic SC)
# Year-1 totals
Total doses: 13 (every 4 weeks × 52 weeks)
Total drug units billed: 780 (13 × 60)
Total drug cost (Q2 2026 ASP+6%): ~$388,998 before sequestration
After ~2% sequestration: ~$381,218 actual paid
Pediatric dosing — expect waste, document with JW
Pediatric XLH dosing is q2wk and almost always produces partial-vial waste because of fixed 10/20/30 mg vial sizes vs continuous weight-based mg targets. JW modifier on every pediatric dose with partial-vial waste is the norm, not the exception. Bill the actual mg administered on the JZ-style admin line and the wasted mg on a separate JW line.
Contraindications & required washout FDA label verified May 2026
Crysvita is contraindicated with conventional XLH therapy components. Document washout in the chart.
Co-administration of Crysvita with oral phosphate AND/OR active vitamin D analogs is
CONTRAINDICATED. This combination causes severe hyperphosphatemia. Both must be discontinued at
least 1 week before the first Crysvita dose. Document discontinuation date, the prescribing physician's
note, and confirmation that the patient stopped both products in the chart.
| Contraindicated medication | Examples | Required washout before Crysvita |
|---|---|---|
| Oral phosphate supplements | K-Phos, Neutra-Phos, sodium phosphate, potassium phosphate | ≥1 week discontinuation; document in chart |
| Active vitamin D analogs (calcitriol) | Rocaltrol, Calcijex (1,25-dihydroxyvitamin D3) | ≥1 week discontinuation; document in chart |
| Active vitamin D analogs (paricalcitol) | Zemplar | ≥1 week discontinuation; document in chart |
| Active vitamin D analogs (doxercalciferol) | Hectorol | ≥1 week discontinuation; document in chart |
| Serum phosphate within/above normal range | (lab finding, not a med) | Do NOT initiate Crysvita; recheck after appropriate interval |
Cholecalciferol (vitamin D3) and ergocalciferol (vitamin D2) are NOT contraindicated.
Only the activated forms (calcitriol, paricalcitol, doxercalciferol) are contraindicated. Patients can
continue OTC vitamin D supplementation. Verify medication list carefully — "vitamin D" on a med list
is ambiguous.
Other warnings & precautions (not boxed)
- Hypersensitivity reactions: rash, urticaria. Discontinue if serious reaction.
- Hyperphosphatemia: monitor serum phosphate q2wk for first month, then q4wk. Reduce dose if above normal.
- Restless leg syndrome: reported new-onset or worsening; consider dose reduction or discontinuation.
- Injection-site reactions: common; rotate injection site (upper arm, abdomen, thigh, buttock).
NDC reference FDA NDC Directory verified May 2026
Crysvita ships in three vial concentrations — choose vials to minimize waste for the calculated dose.
| NDC (10/11-digit) | Strength | Use |
|---|---|---|
69794-101-01 / 69794-0101-01 |
10 mg/mL preservative-free single-dose vial | Pediatric and small-dose scenarios; minimize waste for 5-15 mg doses |
69794-202-01 / 69794-0202-01 |
20 mg/mL preservative-free single-dose vial | Mid-range pediatric and small adult doses (16-25 mg) |
69794-203-01 / 69794-0203-01 |
30 mg/mL preservative-free single-dose vial | Adult dosing (typical 30-90 mg); combine 2-3 vials for >30 mg doses |
Verify NDC at billing time — this list is representative. Ultragenyx may reissue
carton NDCs over time. Check the NDC printed on the carton dispensed to the patient and bill that exact
11-digit NDC. Vial-level NDC vs carton NDC can vary by payer; UHC and Aetna typically expect carton NDC.
Minimize waste by choosing vial mix: A 25 mg dose can be billed as 1×20 mg + 1×10 mg
(5 mg waste → JW for 5 units) OR 1×30 mg vial alone (5 mg waste → JW for 5 units). Same waste
either way. A 28 mg dose is unavoidable waste — bill the wasted mg on JW line. Document vial mix used.
Phase 2
Code the claim
Therapeutic SC admin (96372) — not chemo. Document JZ or JW on every claim.
Administration codes CPT verified May 2026
Crysvita is non-chemo SC. Bill 96372 — NOT 96401 (chemo SC) or any IV infusion code.
| Code | Description | When to use |
|---|---|---|
96372 |
Therapeutic, prophylactic, or diagnostic injection (specify substance or drug); subcutaneous or intramuscular | Primary admin code for Crysvita. Non-chemo SC injection in clinic. |
96401 |
Chemotherapy administration, SC or IM; non-hormonal anti-neoplastic | NOT appropriate. Crysvita is not anti-neoplastic chemotherapy. |
96365 / 96413 |
Therapeutic IV infusion / chemo IV infusion | NOT appropriate. Crysvita is SC only, never IV. |
| (none) | Patient self-administration at home after training | Some payers permit home self-admin after the practice trains the patient. No admin code billed by practice when patient self-administers. |
Why 96372 not 96401: Crysvita is a monoclonal antibody for an endocrine/metabolic
condition, not anti-neoplastic chemotherapy. CPT chemotherapy administration codes (96401–96425)
do not apply. 96372 is the correct code for therapeutic SC injection of non-chemo biologics.
Home self-administration after training: If the patient or caregiver self-administers at
home after in-clinic training, the practice does not bill an admin code on those days. Bill J0584 (drug)
only on training/clinic dose days; on self-admin days, the drug typically goes through specialty pharmacy
and is not billed by the practice. Verify per payer.
Modifiers CMS verified May 2026
JZ — required when no waste
Effective July 1, 2023, CMS requires the JZ modifier on all single-dose container claims when no drug is discarded. Crysvita ships in 10/20/30 mg single-dose vials. JZ applies when the calculated dose exactly matches the vial(s) used (e.g., 30 kg pediatric → 24 mg using one 30 mg vial would be JW; but a 60 kg adult on 60 mg using two 30 mg vials = JZ no waste).
JW — required when partial-vial waste occurs (common with Crysvita)
JW reports the discarded portion of a single-dose vial. Crysvita weight-based dosing with fixed-size vials produces partial-vial waste on a majority of doses, particularly in pediatric XLH and TIO scenarios. Example: a 35 kg pediatric patient receiving 28 mg uses one 30 mg vial and discards 2 mg — bill the JW line with 2 units of waste alongside the JZ-style admin line for 28 units administered. One of JZ or JW must be on every J0584 claim.
Common error: Forgetting to bill the discarded portion. CMS audits often catch this for
weight-based drugs in fixed-size vials. Wasted drug is reimbursable but must be reported on the JW line.
Pediatric XLH practices should expect JW on most claims.
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 (e.g., titration assessment, lab review, dose adjustment). Routine pre-injection check is bundled into 96372.
340B modifiers (JG, TB)
For 340B-acquired Crysvita, follow your MAC's current 340B modifier policy. Crysvita is a high-cost biologic and is included in most 340B-covered entity formularies; verify pricing impact.
ICD-10-CM by indication FY2026 verified May 2026
Use the most specific code supported by encounter documentation. Both indications require lab + imaging documentation in the PA.
| Indication | ICD-10 (primary) | Supplementary codes |
|---|---|---|
| X-linked hypophosphatemia (XLH) | E83.31 familial hypophosphatemia |
M89.9 bone disease NOS;
M85.x other disorders of bone density and structure;
M89.20 other disorder of bone development — site unspecified;
Q78.5 metaphyseal dysplasia (if rickets-related deformities)
|
| Tumor-induced osteomalacia (TIO) — tumor identified, unresectable | D48.0 neoplasm of uncertain behavior of bone & articular cartilage |
D49.81 neoplasm of unspecified behavior of connective & soft tissue;
M83.x adult osteomalacia;
E83.39 other disorders of phosphorus metabolism
|
| Tumor-induced osteomalacia (TIO) — cryptic tumor (unidentified after workup) | D49.81 neoplasm of unspecified behavior of connective & soft tissue (cryptic FGF23 source) |
M83.9 adult osteomalacia, unspecified; E83.39 other disorders of phosphorus metabolism |
ICD-10 alone is not sufficient. All major payers require additional documentation in the
PA submission: serum phosphate (below age-adjusted normal), serum FGF23 (elevated), genetic testing for
XLH (PHEX gene mutation OR clinical/family history with biochemistry), specialist prescriber
(geneticist/endocrinologist/nephrologist), AND documented discontinuation of oral phosphate + active
vitamin D analogs.
Site of care & place of service Verified May 2026
Crysvita is a 1-2 minute SC injection — minimal site-of-care complexity. Most practices administer in office (POS 11) on titration/maintenance schedule. Some commercial payers permit home self-administration after in-clinic training, particularly for adult XLH patients on stable monthly dosing.
| Setting | POS | Claim form | Payer steering |
|---|---|---|---|
| Endocrinology / nephrology / genetics office | 11 | CMS-1500 / 837P | Preferred — SC injection fits cleanly |
| Pediatric specialty clinic | 11 | CMS-1500 / 837P | Preferred for XLH pediatric titration |
| Hospital outpatient (on-campus) | 22 | UB-04 / 837I | Acceptable for academic centers; some commercial site-of-care UM |
| Patient home (self-admin after training) | 12 | (specialty pharmacy bills drug; no admin code) | Possible after training; commercial-only typically |
| Patient home (HCP-administered) | 12 | CMS-1500 with home-infusion vendor | Rare for SC monthly injection |
Self-administration economics: Once the patient is trained, ongoing doses can ship to
the patient via specialty pharmacy. Drug then bills under specialty pharmacy/medical benefit, not the
practice. Practice still bills training visits and periodic in-clinic checks. Verify with each payer
whether they prefer practice-buy-and-bill or specialty pharmacy distribution.
Claim form field mapping Ultragenyx UltraCare 2025
From Ultragenyx UltraCare HCP coding & coverage guidance.
| Information | CMS-1500 box | Notes |
|---|---|---|
| NPI | 17b | Rendering provider (specialist) |
| NDC qualifier + 11-digit NDC + UoM + qty | 24A shaded area | N4 + carton NDC + ML + total mL administered |
| HCPCS J0584 + JZ (no waste) or JW (with waste) | 24D (drug line) | Mark JZ or JW; pediatric expect JW frequently |
| Drug units (administered) | 24G | Actual mg administered (not vial size) |
| JW waste line (separate) | 24D / 24G | Wasted mg on separate line with JW modifier |
| CPT 96372 (admin line) | 24D (admin line) | Therapeutic SC injection, non-chemo |
| ICD-10 | 21 | E83.31 (XLH primary), D48.0 / D49.81 (TIO) |
| PA number | 23 | Required by all major payers |
Phase 3
Get paid
PA is universal. Genetic test (PHEX) for XLH or imaging workup (TIO) is a hard prerequisite.
Payer policy snapshot Reviewed May 2026
All major payers require PA. Coverage is universal for confirmed XLH/TIO with appropriate documentation.
| Payer | PA? | Key requirements | Reauth |
|---|---|---|---|
| UnitedHealthcare Medical Drug Coverage Policy |
Yes | Confirmed XLH (PHEX gene OR family history + hypophosphatemia) or TIO (FGF23-elevated unresectable tumor); specialist prescriber; documented discontinuation of oral phosphate + active vitamin D ≥1 wk; baseline serum phosphate | Annual; demonstrate clinical benefit (improved phosphate, reduced symptoms, healing on imaging) |
| Aetna CPB Medical Drug policy |
Yes | Same as UHC; specifically requires geneticist, endocrinologist, or nephrologist; XLH genetic testing OR clear clinical phenotype | Annual; serum phosphate documentation |
| BCBS plans Vary by plan |
Yes | Generally aligned with FDA label; some plans require trial of conventional therapy first (oral phosphate + calcitriol) for adult XLH | Annual |
| Medicare (LCD/MAC) Coverage by MAC |
Generally not formal PA but documentation required | Coverage for FDA-labeled indications with appropriate ICD-10 + biochemistry; specialist documentation typical | Ongoing review; lifelong therapy for XLH |
Step therapy (varies by payer)
Some commercial payers (notably select BCBS plans) require trial and failure of conventional therapy (oral phosphate + active vitamin D) for adult XLH before approving Crysvita. Pediatric XLH and all TIO typically do NOT require step therapy because conventional therapy has limited efficacy in growing children and is not effective for TIO. Verify per payer.
Required documentation in PA submission
- Confirmed diagnosis: PHEX gene mutation testing (XLH) OR FGF23-elevated unresectable tumor (TIO)
- Lab values: serum phosphate (below age-adjusted normal), serum FGF23 (elevated), serum 1,25-OH vitamin D, alkaline phosphatase
- Specialist prescriber: geneticist, endocrinologist, or nephrologist
- Documented discontinuation of oral phosphate AND active vitamin D analogs ≥1 week prior
- For TIO: imaging workup (PET-CT, octreotide scan, gallium-68 DOTATATE) showing tumor or documenting cryptic search
- For pediatric XLH: growth chart, evidence of rickets (radiographic), Healing of Rickets Score (HMP) baseline
Medicare reimbursement CMS Q2 2026 (live)
Quarterly ASP from CMS Part B Drug Pricing File. Refreshes automatically each quarter.
Q2 2026 payment snapshot — J0584
Effective April 1 – June 30, 2026 · Based on 4Q25 ASP submissions
ASP + 6%
$498.716
per mg / per unit
60 mg dose (XLH adult typical)
$29,922.96
60 units × ASP+6%
90 mg dose (max)
$44,884.44
90 units × ASP+6%
Annualized cost (representative XLH adult): 60 mg q4wk × 13 doses = ~$388,998/year
(Medicare ASP+6%). 90 mg max-dose q4wk × 13 doses = ~$583,498/year. Pediatric XLH on
q2wk schedule has ~26 doses/year and lower per-dose mg, but smaller patients can still cost
~$300K–$500K annually. After ~2% sequestration, actual paid drops by ~$8K–$12K.
Crysvita is among the highest per-mg drugs in the Medicare Part B catalog at ~$499/mg.
Lifelong therapy + small-dose pediatric population means total spend per patient is high; precise unit
counting and waste documentation matters more than for typical biologics.
Coverage
No NCD specific to burosumab-twza. Coverage falls under MAC LCDs for biologics + the generic drug-coverage framework. All MACs cover J0584 for FDA-approved on-label XLH and TIO indications with appropriate documentation (specialist prescriber, ICD-10, biochemistry, washout of contraindicated meds).
Code history
- J0584 — permanent code, "Injection, burosumab-twza 1 mg." Pre-permanent-code period (2018–2019) used unclassified J3490.
Patient assistance — Ultragenyx UltraCare Ultragenyx verified May 2026
- UltraCare: 1-888-756-8657 — benefits investigation, prior authorization assistance, appeal support, nurse navigator
- Crysvita Co-Pay Program: commercial copay support; eligible commercially-insured patients pay $0 for first dose, ongoing copay assistance up to program limits (excludes Medicare, Medicaid, federal program patients)
- Ultragenyx Patient Assistance Program (PAP): free product for uninsured / underinsured patients meeting income requirements
- Foundations: for Medicare patients, refer to PAN, HealthWell, NORD — verify open XLH/rare disease funds quarterly. PAN periodically opens an XLH/hypophosphatemia fund.
- Web: ultracare-us.com / crysvita.com
Need to model what a specific patient will actually pay after copay assistance, deductible, coinsurance,
and OOP max for Crysvita's high per-dose cost? Run a CareCost Estimate
— J0584 pre-loaded.
Phase 4
Fix problems
Missing washout documentation, wrong admin code (chemo vs SC), and JW omission are the top three.
Common denials & how to fix them
| Denial reason | Common cause | Fix |
|---|---|---|
| Washout of contraindicated meds not documented | PA submitted without chart note showing oral phosphate + active vitamin D discontinuation date | Submit chart note with discontinuation date, prescriber attestation, and confirmation patient stopped both products ≥1 week before first dose. Common cause of initial denial. |
| Wrong admin code (96401 chemo SC) | Chemo SC billed instead of therapeutic SC | Resubmit with 96372. Crysvita is non-chemo; chemo admin codes do not apply. |
| Wrong admin code (IV infusion code) | 96365 or 96413 billed instead of 96372 | Crysvita is SC only, never IV. Resubmit with 96372. |
| JW missing on pediatric or weight-based dose | Wasted drug not reported when calculated dose < vial size | Add JW line for discarded units. JZ on the administered units; JW on the wasted units. Required since 7/1/2023. |
| JZ missing on no-waste claim | Single-dose vial claim without JZ when calculated dose matches vial(s) | Resubmit with JZ. One of JZ or JW required on every J0584 claim. |
| PA criteria not met (XLH genetic confirmation missing) | PHEX gene mutation testing not in PA submission | Submit PHEX gene test result OR family history + clinical phenotype documentation (clear inheritance pattern + biochemistry + radiographic rickets). |
| PA criteria not met (TIO imaging workup missing) | No imaging documenting tumor or cryptic search | Submit PET-CT, octreotide scan, or gallium-68 DOTATATE imaging report; if tumor identified, surgical opinion documenting unresectability. |
| Specialist prescriber not documented | Primary care physician submitted PA | Resubmit through geneticist, endocrinologist, or nephrologist. Most payers will not approve PCP-submitted PA for Crysvita. |
| Step therapy required (commercial) | Some BCBS plans require conventional therapy trial first for adult XLH | Submit prior conventional therapy trial documentation OR clinical justification for skipping (severe disease, intolerance, contraindication). Pediatric and TIO usually exempt. |
| Wrong NDC format | Wrong-strength vial NDC submitted | Verify carton NDC for the dispensed vial(s). Use 69794-101-01 (10 mg/mL), 69794-202-01 (20 mg/mL), or 69794-203-01 (30 mg/mL). |
Frequently asked questions
What is the HCPCS code for Crysvita?
Crysvita (burosumab-twza) is billed under HCPCS J0584 — "Injection, burosumab-twza,
1 mg." Each milligram equals one billable unit. A 60 kg adult on the standard XLH dose (1 mg/kg q4wk,
rounded to 60 mg) is billed as 60 units of J0584 once every 4 weeks.
Is Crysvita given IV or subcutaneously?
Crysvita is subcutaneous only — it is NOT an IV drug. Administered SC into the
upper arm, abdomen, thigh, or buttock. Bill CPT 96372 (therapeutic SC/IM injection,
non-chemo) for the administration. Do not bill 96401 (chemo SC) — Crysvita is a non-chemo
monoclonal antibody. Some payers permit home self-administration after training, in which case no admin
code is billed by the practice.
What is the dose for Crysvita?
Indication- and weight-specific. XLH pediatric (≥6 mo, <18 yr): start 0.8 mg/kg SC every 2 weeks (max 2 mg/kg per dose, max 90 mg per dose); titrate based on serum phosphate q4wk. XLH adults: 1 mg/kg SC every 4 weeks, rounded to nearest 10 mg, max 90 mg per dose. Tumor-induced osteomalacia (TIO): 0.5 mg/kg SC q4wk pediatric (≥2 yr) OR 0.5 mg/kg SC q2wk adult, titrate based on response.
Is JZ or JW required for Crysvita?
Yes — one of JZ or JW must be on every J0584 claim per CMS's July 2023 single-dose container policy. Crysvita ships in fixed-size 10/20/30 mg single-dose vials, so weight-based dosing frequently produces partial-vial waste. Example: a 25 kg child receiving 20 mg uses one 20 mg vial with no waste (JZ); a 35 kg child receiving 28 mg uses one 30 mg vial and discards 2 mg (JW for 2 units of waste).
What is the Medicare reimbursement for J0584?
For Q2 2026, the Medicare Part B payment limit for J0584 is $498.716 per mg (ASP + 6%). A 60 mg adult dose reimburses at approximately $29,922.96; a 90 mg max-dose at approximately $44,884.44. Crysvita is among the highest per-mg drugs in the Medicare catalog due to small dose, lifelong indication, and ultra-rare disease status. Sequestration (~2%) reduces actual paid to roughly ASP + 4.3%.
What conditions does Crysvita treat?
Two FDA-approved indications: (1) X-linked hypophosphatemia (XLH) in adults and pediatric patients ≥6 months — caused by PHEX gene mutation leading to FGF23 elevation, hypophosphatemia, and rickets/osteomalacia. (2) Tumor-induced osteomalacia (TIO) in adults and pediatric ≥2 years when the tumor cannot be curatively resected or located. Both indications require lab-documented hypophosphatemia and elevated FGF23.
What are the contraindications for Crysvita?
Crysvita is CONTRAINDICATED with concurrent oral phosphate supplementation OR active vitamin D analogs (calcitriol, paricalcitol, doxercalciferol). These conventional XLH therapies must be discontinued at least 1 week before starting Crysvita. Document discontinuation in the chart with date and prescriber note. Failure to discontinue causes severe hyperphosphatemia. Also contraindicated when serum phosphate is within or above the normal range for age. Cholecalciferol (vitamin D3) and ergocalciferol (vitamin D2) are NOT contraindicated — only the activated forms.
Does Crysvita require prior authorization?
Yes — every major payer requires PA for Crysvita. Universal requirements: confirmed XLH diagnosis (PHEX gene mutation testing OR family history with hypophosphatemia and physical findings) or TIO diagnosis (FGF23-elevated tumor that cannot be resected); documented hypophosphatemia (serum phosphate below age-adjusted normal); elevated serum FGF23; specialist prescriber (geneticist, endocrinologist, or nephrologist); documented discontinuation of oral phosphate and active vitamin D. Crysvita is lifelong therapy for XLH, so reauthorization is annual.
Reference
Sources & methodology
Every claim on this page is sourced. Methodology and review history below.
Source documents
- Crysvita HCP page — Ultragenyx Pharmaceutical
- DailyMed — CRYSVITA (burosumab-twza) Prescribing Information
- FDA Crysvita label PDF (s011, 2020 TIO expansion)
- UltraCare — Ultragenyx Patient Support Program
- CMS — Medicare Part B Drug ASP Pricing File
- SEER CanMED — HCPCS J0584 reference
- UnitedHealthcare — Medical Drug Coverage Policy (burosumab)
- Aetna — Clinical Policy Bulletin (burosumab / Crysvita)
- FDA National Drug Code Directory
- NORD — X-linked hypophosphatemia (XLH) overview
- Endocrine Society / ICCBH — XLH clinical practice consensus
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
| Element | Cadence | How it's refreshed |
|---|---|---|
| Medicare ASP pricing | Quarterly | Auto-bound to CareCost ASP layer; updates on CMS file release. |
| Payer policies (UHC, Aetna, BCBS) | Semi-annual | Manual review against published payer policy documents. |
| HCPCS / CPT / modifier rules | Annual | Reviewed against CMS HCPCS quarterly files and AMA CPT releases. |
| NDC, dosing, FDA label, indication list | Event-driven | Tied to manufacturer document version + FDA label revision date. |
Reviewer
Pending SME review. This page is staff-authored from primary sources (FDA, CMS,
manufacturer, payer documents — all linked above). Editorial review in progress. Until that review is complete, treat this as a draft reference and verify each cited
source for high-stakes claims.
Change log
- — Initial publication. ASP data: Q2 2026. Manufacturer source: Ultragenyx UltraCare 2025. FDA label: includes 2018 XLH initial approval (BLA 761068), 2018 pediatric ≥6 mo expansion, 2020 TIO indication addition. First-in-class anti-FGF23 monoclonal antibody.
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 is verified against the current FDA label revision. We do not paraphrase from billing-software vendor blogs.