845 MS-DRG: OTHER MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASTIC DIAGNOSES WITHOUT CC/MCC
MS-DRG 845 groups Medicare inpatient hospital stays for: OTHER MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASTIC DIAGNOSES WITHOUT CC/MCC. This is a medical MS-DRG. It falls under MDC 17 (Myeloproliferative Diseases and Disorders, Poorly Differentiated Neoplasms).
Payment & Classification Data
Official CMS values from the FY2027 IPPS Final Rule Table 5.
| Major Diagnostic Category | MDC 17 — Myeloproliferative Diseases and Disorders, Poorly Differentiated Neoplasms |
| DRG Type | Medical |
| Severity Level | None |
| Relative Weight | 0.8447 |
| Relative Weight (10% Cap Applied) | 0.8447 |
| Geometric Mean Length of Stay | 2.3 days |
| Arithmetic Mean Length of Stay | 3 days |
| Post-Acute Transfer DRG | No |
| Special Pay Transfer DRG | No |
Defining Codes (FY2027)
110 diagnosis codes can drive assignment here: C37, C45.7, C45.9, C48.0, C76.40, C76.41, C76.42, C76.50, C76.51, C76.52, C76.8, C79.83 and 98 more.
From the CMS MS-DRG Definitions Manual (Appendices B and E). Assignment also depends on severity, discharge status and the rest of the claim.
Contextual Map
Every relationship of 845 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.
Major Diagnostic Category
- MDC 17 — Myeloproliferative Diseases and Disorders, Poorly Differentiated Neoplasms[MDC]— CMS MS-DRG Definitions Manual · FY2027
Defining diagnoses (110)
- C37 — Malignant neoplasm of thymus[Grouper diagnosis]— CMS MS-DRG Definitions Manual (Appendix B) · FY2027
- C45.7 — Mesothelioma of other sites[Grouper diagnosis]— CMS MS-DRG Definitions Manual (Appendix B) · FY2027
- C45.9 — Mesothelioma, unspecified[Grouper diagnosis]— CMS MS-DRG Definitions Manual (Appendix B) · FY2027
- C48.0 — Malignant neoplasm of retroperitoneum[Grouper diagnosis]— CMS MS-DRG Definitions Manual (Appendix B) · FY2027
- C76.40 — Malignant neoplasm of unspecified upper limb[Grouper diagnosis]— CMS MS-DRG Definitions Manual (Appendix B) · FY2027
- C76.41 — Malignant neoplasm of right upper limb[Grouper diagnosis]— CMS MS-DRG Definitions Manual (Appendix B) · FY2027
- C76.42 — Malignant neoplasm of left upper limb[Grouper diagnosis]— CMS MS-DRG Definitions Manual (Appendix B) · FY2027
- C76.50 — Malignant neoplasm of unspecified lower limb[Grouper diagnosis]— CMS MS-DRG Definitions Manual (Appendix B) · FY2027
- and 102 more
DRG family
- DRG 843 — OTHER MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASTIC DIAGNOSES WITH MCC[DRG family]: “OTHER MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASTIC DIAGNOSES WITH MCC — same CMS DRG family (843-845), split by severity.”— CMS MS-DRG Definitions Manual (DRG family 843-845) · FY2027
- DRG 844 — OTHER MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASTIC DIAGNOSES WITH CC[DRG family]: “OTHER MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASTIC DIAGNOSES WITH CC — same CMS DRG family (843-845), split by severity.”— CMS MS-DRG Definitions Manual (DRG family 843-845) · FY2027
Read from: CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v44. All data sources · How to read the labels · How MedCoder verifies its implementation
Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources