M33.20: Polymyositis, organ involvement unspecified
M33.20, polymyositis, organ involvement unspecified, is listed as a covered diagnosis in 9 Medicare billing and coding articles that apply to 33 HCPCS Level II codes, including J1569 (Injection, immune globulin, (gammagard liquid/gammagard…), J1561 (Injection, immune globulin, (gamunex-c/gammaked)…), J1459 (Injection, immune globulin (privigen), intravenous…). The articles come from 4 Medicare contractors. A listed diagnosis supports medical necessity only; coverage still depends on the LCD's criteria and on documentation in the medical record.
HCPCS Level II codes with M33.20 as a covered diagnosis
| Code | Description | Medicare coverage | DMEPOS fee 2026 (state range) | Articles listing it |
|---|---|---|---|---|
| J1569 | Injection, immune globulin, (gammagard liquid/gammagard liquid erc), 500 mg | Special coverage instructions apply | — | 4 |
| J1561 | Injection, immune globulin, (gamunex-c/gammaked), non-lyophilized (e.g., liquid), 500 mg | Special coverage instructions apply | — | 4 |
| J1459 | Injection, immune globulin (privigen), intravenous, non-lyophilized (e.g., liquid), 500 mg | Carrier judgment | — | 4 |
| J1557 | Injection, immune globulin, (gammaplex), intravenous, non-lyophilized (e.g., liquid), 500 mg | Carrier judgment | — | 4 |
| J1556 | Injection, immune globulin (bivigam), 500 mg | Carrier judgment | — | 4 |
| J1568 | Injection, immune globulin, (octagam), intravenous, non-lyophilized (e.g., liquid), 500 mg | Carrier judgment | — | 4 |
| J1566 | Injection, immune globulin, intravenous, lyophilized (e.g., powder), not otherwise specified, 500 mg | Special coverage instructions apply | — | 4 |
| J1554 | Injection, immune globulin (asceniv), 500 mg | Carrier judgment | — | 4 |
| J1599 | Injection, immune globulin, intravenous, non-lyophilized (e.g., liquid), not otherwise specified, 500 mg | Carrier judgment | — | 4 |
| J1576 | Injection, immune globulin (panzyga), intravenous, non-lyophilized (e.g., liquid), 500 mg | Special coverage instructions apply | — | 3 |
| J1552 | Injection, immune globulin (alyglo), 500 mg | Carrier judgment | — | 3 |
| J1577 | Injection, immune globulin (qivigy), 100 mg | Carrier judgment | — | 3 |
| J9312 | Injection, rituximab, 10 mg | Special coverage instructions apply | — | 3 |
| Q5123 | Injection, rituximab-arrx, biosimilar, (riabni), 10 mg | Carrier judgment | — | 3 |
| Q5119 | Injection, rituximab-pvvr, biosimilar, (ruxience), 10 mg | Carrier judgment | — | 3 |
| Q5115 | Injection, rituximab-abbs, biosimilar, (truxima), 10 mg | Special coverage instructions apply | — | 3 |
| J1553 | Injection, immune globulin (yimmugo), 100 mg | Carrier judgment | — | 1 |
| J2791 | Injection, rho(d) immune globulin (human), (rhophylac), intramuscular or intravenous, 100 iu | Special coverage instructions apply | — | 1 |
| J2792 | Injection, rho d immune globulin, intravenous, human, solvent detergent, 100 iu | Special coverage instructions apply | — | 1 |
| J9260 | Injection, methotrexate sodium, 50 mg | Special coverage instructions apply | — | 1 |
| J9215 | Injection, interferon, alfa-n3, (human leukocyte derived), 250,000 iu | Special coverage instructions apply | — | 1 |
| J9311 | Injection, rituximab 10 mg and hyaluronidase | Special coverage instructions apply | — | 1 |
| J3590 | Unclassified biologics | Carrier judgment | — | 1 |
| J1575 | Injection, immune globulin/hyaluronidase, (hyqvia), 100 mg immuneglobulin | Carrier judgment | — | 1 |
| J1572 | Injection, immune globulin, (flebogamma/flebogamma dif), intravenous, non-lyophilized (e.g., liquid), 500 mg | Special coverage instructions apply | — | 1 |
8 more codes are listed. See every code with payment by region in Caduvo.
Medicare policy articles listing M33.20
- A57187: Billing and Coding: Immune Globulin Intravenous (IVIg) (Noridian Healthcare Solutions, LLC (MAC - Part A, MAC - Part B); 13 Level II codes). LCD with the same title: L34314
- A56718: Billing and Coding: Intravenous Immunoglobulin (IVIG) (Palmetto GBA (MAC - Part A, MAC - Part B); 13 Level II codes). LCD with the same title: L34580
- A59105: Billing and Coding: Off-Label Use of Intravenous Immune Globulin (IVIG) (Wellpoint Federal (MAC - Part A, MAC - Part B); 11 Level II codes). LCD with the same title: L39314
- A55639: Billing and Coding: Chemotherapy Agents for Non-Oncologic Conditions (WPS Insurance Corporation (MAC - Part A, MAC - Part B); 6 Level II codes)
- A56380: Billing and Coding: Rituximab (Palmetto GBA (MAC - Part A, MAC - Part B); 6 Level II codes). LCD with the same title: L35026
- A59101: Billing and Coding: Off-label Use of Rituximab and Rituximab Biosimilars (Wellpoint Federal (MAC - Part A, MAC - Part B); 4 Level II codes). LCD with the same title: L38920, L39297
- A57554: Billing and Coding: Immune Globulins (WPS Insurance Corporation (MAC - Part A, MAC - Part B); 20 Level II codes). LCD with the same title: L34771
- A57668: Billing and Coding: Nerve Conduction Studies and Electromyography (Wellpoint Federal (MAC - Part A, MAC - Part B); 1 Level II codes). LCD with the same title: L34594, L34859, L35048, L35081
- A56619: Billing and Coding: Nerve Conduction Studies and Electromyography (Palmetto GBA (MAC - Part A, MAC - Part B); 1 Level II codes). LCD with the same title: L34594, L34859, L35048, L35081
A diagnosis listed as covered in a billing and coding article supports medical necessity for the article's codes; it does not guarantee payment. Coverage depends on the LCD's criteria, the contractor's jurisdiction and documentation in the medical record.
Other M33 diagnoses (Dermatopolymyositis)
- M33.21 — Polymyositis with respiratory involvement
- M33.22 — Polymyositis with myopathy
- M33.29 — Polymyositis with other organ involvement
- M33.00 — Juvenile dermatomyositis, organ involvement unspecified
- M33.01 — Juvenile dermatomyositis with respiratory involvement
- M33.02 — Juvenile dermatomyositis with myopathy
- M33.03 — Juvenile dermatomyositis without myopathy
- M33.09 — Juvenile dermatomyositis with other organ involvement
- M33.10 — Other dermatomyositis, organ involvement unspecified
- M33.11 — Other dermatomyositis with respiratory involvement
- M33.12 — Other dermatomyositis with myopathy
- M33.13 — Other dermatomyositis without myopathy
- M33.19 — Other dermatomyositis with other organ involvement
- M33.90 — Dermatopolymyositis, unspecified, organ involvement unspecified
- M33.91 — Dermatopolymyositis, unspecified with respiratory involvement
- M33.92 — Dermatopolymyositis, unspecified with myopathy
- M33.93 — Dermatopolymyositis, unspecified without myopathy
- M33.99 — Dermatopolymyositis, unspecified with other organ involvement
Frequently asked questions
Does Medicare cover M33.20 (Polymyositis, organ involvement unspecified)?
Medicare covers items and services, not diagnoses. 9 Medicare billing and coding articles list M33.20 as a covered diagnosis for 33 HCPCS Level II codes: the diagnosis can support medical necessity for those codes, but payment still depends on the LCD's coverage criteria and the medical record.
Which HCPCS codes can be billed with ICD-10 M33.20?
The Level II codes from the policies most specific to this diagnosis are J1569 (Injection, immune globulin, (gammagard liquid/gammagard…, 4 articles); J1561 (Injection, immune globulin, (gamunex-c/gammaked)…, 4 articles); J1459 (Injection, immune globulin (privigen), intravenous…, 4 articles); J1557 (Injection, immune globulin, (gammaplex), intravenous…, 4 articles); J1556 (Injection, immune globulin (bivigam), 500 mg, 4 articles). Code choice depends on the item supplied; check each code's descriptor.
Which Medicare policy articles list M33.20?
A57187 (Billing and Coding: Immune Globulin Intravenous (IVIg)); A56718 (Billing and Coding: Intravenous Immunoglobulin (IVIG)); A59105 (Billing and Coding: Off-Label Use of Intravenous Immune Globulin (IVIG)), and 6 more articles.
What is ICD-10-CM code M33.20?
M33.20 is the ICD-10-CM code for polymyositis, organ involvement unspecified, in category M33 (Dermatopolymyositis), chapter 13: Diseases of the musculoskeletal system and connective tissue.
Next steps
- Run a reimbursement report for a device billed under J1569
- Watch J1569 for fee, coverage and descriptor changes
- Build a full Medicare revenue model for J1569
Sources: CMS Medicare Coverage Database billing and coding articles (covered ICD-10 code lists and HCPCS links); ICD-10-CM FY2026; CMS HCPCS Level II release October 2026; CMS DMEPOS fee schedule 2026 (non-rural state fees). Not billing or legal advice.
Chapter 13: Diseases of the musculoskeletal system and connective tissue · All diagnoses · HCPCS lookup