Xembify (SCIG 20%) — HCPCS J1558
CareCost Estimate · Billing Cheat Sheet
Grifols (sister to Gamunex-C J1561)
20% (200 mg/mL) liquid · 1g, 2g, 4g, 5g, 10g, 20g vials
Subcutaneous pump (NOT IV)
Reviewed: May 2, 2026
ASP: Q3 2026
HCPCS
J1558
1 unit = 100 mg (NOT 500)
PI Weekly
~70 units
100 mg/kg/wk (70 kg)
Modifier
JZ
Single-dose vial
Admin CPT
96369+96370
SCIG pump (not 96365)
Medicare ASP+6%
$15.243
/100 mg unit · $154/g
BILLER TRAPS: (1) J1558 = 100 mg per unit (different from IVIG codes which use 500 mg). (2) SCIG admin codes are 96369/96370/96371 (pump infusion) — NOT 96365/96366 (IV) and NOT 96372 (SC injection). (3) Xembify is PI-only on label — NO CIDP coverage (route to Hizentra/HyQvia for CIDP).
Codes & NDC
| HCPCS | J1558 — "Inj. xembify, 100 mg" (1 unit = 100 mg) |
|---|
| Concentration | 20% liquid (200 mg/mL); caprylate/chromatography purified, glycine |
|---|
| Vial sizes | 1g/5mL, 2g/10mL, 4g/20mL, 5g/25mL, 10g/50mL, 20g/100mL (broadest 20% SCIG range) |
|---|
| NDC labeler | 13533 (Grifols Therapeutics) — verify exact package NDC at fill |
|---|
| Storage | Refrigerate 2-8°C; room-temp window per current label |
|---|
SCIG admin codes (CRITICAL)
| Code | When |
|---|
96369 | SC infusion via mechanical pump, initial up to 1 hr |
96370 | Each additional hr |
96371 | Add'l pump set-up (e.g., 2nd site, 2nd pump) |
NOT 96372 (that's manual SC injection, not pump). NOT 96365/96366 (IV). Most billers initially miscode SCIG with IV codes — 96369-96371 are SCIG-specific. Practices that also infuse Gamunex-C (J1561 IVIG) are particularly prone to this drift.
Indication & dosing (PI ONLY)
| Indication | Dose | Schedule |
|---|
| PI conversion from IVIG | 1.37 × IVIG monthly ÷ 4 | Weekly |
| PI maint. (adult + ped ≥2) | 100-200 mg/kg/wk | Weekly typical |
| Frequency | weekly / biweekly | Patient preference |
| CIDP | NOT FDA-approved for Xembify — route to Hizentra (J1559) or HyQvia (J1575) |
FDA approval: July 2019 (BLA 125687). Sister to Gamunex-C (Grifols J1561) — same caprylate/chromatography purification platform.
SCIG brand cost matrix (Q3 2026)
| Brand | HCPCS | Conc. | $/mg ASP+6% |
|---|
| Cutaquig | J1551 | 16.5% | ~$0.139 |
| Hizentra (proline) | J1559 | 20% | ~$0.145 |
| Xembify (glycine) | J1558 | 20% | ~$0.154 |
| Cuvitru (glycine) | J1555 | 20% | ~$0.176 |
| Gamunex-C SC | J1561 | 10% | ~$0.099 (500 mg basis) |
Cost positioning: Xembify is the lower-cost glycine-stabilized 20% SCIG (below Cuvitru); Hizentra (proline) is cheaper but unsuitable for hyperprolinemia patients.
SCIG vs IVIG comparison
| Factor | SCIG (Xembify) | IVIG |
|---|
| Frequency | Weekly | q3-4wk |
| Trough variation | Low (steady state) | High (peak/trough) |
| Side effects | Local (site rxn) | Systemic (HA, infusion rxn) |
| Setting | Home (POS 12) | Office/AIC/home |
| Per-mg cost | $0.154/mg | ~$0.080-0.10/mg |
ICD-10 (PI ONLY)
| Code | For |
|---|
D80.x | PI — antibody defects (D80.0 X-linked, D80.1 hypogamma, D80.3 IgG subclass) |
D81.x | PI — combined immunodeficiencies |
D82.x | PI — other major defects |
D83.x | CVID family |
G61.81 | CIDP — NOT covered for J1558 — route to Hizentra/HyQvia |
Home self-administration (the norm)
- Patient training required (typically 1-3 sessions with infusion nurse)
- Up to 6 simultaneous infusion sites per session (abdomen, thighs, hip)
- 60-120 min per session via mechanical pump (CRONO-S, Freedom60, etc.)
- Major billing impact: home health vs office (POS 12 most common)
- Some plans: DME benefit (pump) + medical benefit (drug)
- Home-infusion provider (Coram, Option Care, Optum, BriovaRx) authorized at PA
Vial-fit advantage: Xembify's 5g and 20g sizes (unique in 20% SCIG class) often eliminate JW waste lines vs Hizentra/Cuvitru combos.
Payer requirements (May 2026)
| Payer | PA | Requirements |
|---|
| UnitedHealthcare | Yes | PI dx + IgG levels + vaccine challenge + training docs; Xembify often preferred on cost grounds |
| Aetna | Yes | Same + step from IVIG attempt may apply; clinician brand choice |
| Cigna | Yes | Home infusion vendor pre-auth; SCIG/IVIG parity |
| BCBS plans | Yes | Plan-specific; cost-conscious plans favor Xembify |
| Medicare LCD | Yes (DME) | FDA-approved PI indication; DME pump benefit separate |
Medicare reimbursement (Q3 2026)
| Field | Value |
|---|
| ASP + 6% | $15.243 / 100 mg unit = $153.67/g |
| 7 g weekly (70 kg, 100 mg/kg) | $1,075.69 |
| 10 g weekly (PI) | $1,536.70 |
| Annual (10 g weekly × 52) | ~$79,908 |
Patient assistance — Grifols PathConnect
- Phone: 1-855-477-2672 (PathConnect)
- Benefits investigation, PA support, appeal assistance
- Xembify Co-Pay Assistance Program (commercial only)
- Grifols PAP for uninsured / income-tested
- Independent foundations (Medicare): PAN, HealthWell
- Web: xembify.com / grifols.com
Reviewed by Erin Rose, CareCost Estimate founder. Every figure triangulated against FDA labeling, CMS ASP files & payer policy — see
methodology.