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MS-DRG 850 · MDC 17 · Surgical

MS-DRG 850: Acute Leukemia with Other Procedures

Reviewed by QuickIntell RCM Editorial Team · Last reviewed

Data effective
Data currency: IPPS Table 5 FY2027 final rule (effective October 1, 2026); Definitions Manual v44 (effective October 1, 2026). Next CMS release: April 1, 2027 (v44.1 mid-year update), then the FY2028 final rule in August 2027.

Key facts for DRG 850

FY2027 relative weight
8.4080
Higher than 98% of all MS-DRGs
Change vs FY2026
-2.9%
FY2026 weight 8.6590
Geometric mean LOS
15.6 days
Arithmetic mean 23.2 days
MDC
17
Myeloproliferative Diseases and Disorders, Poorly Differentiated Neoplasms
Severity level
single severity level
Transfer policy
Not a transfer DRG

TL;DR

MS-DRG 850 is a surgical group in MDC 17 (Myeloproliferative Diseases and Disorders, Poorly Differentiated Neoplasms) at a single-severity group of its family. CMS assigns it a FY2027 relative weight of 8.4080 with a geometric mean length of stay of 15.6 days and an arithmetic mean of 23.2. Its weight moved down 2.9% from FY2026 (8.6590). That weight is higher than 98% of all surgical and medical MS-DRGs. CMS does not split this group by severity. The v44 Definitions Manual assigns it through 33 principal diagnosis codes.

What changed from FY2026 to FY2027

CMS recalibrates every MS-DRG weight annually from the prior year's MedPAR claims. For DRG 850 the FY2027 relative weight is 8.4080 against 8.6590 in FY2026, a fall of 2.90%, which exceeds the 2% threshold worth re-checking in contract models.

FY2026 versus FY2027 payment factors for MS-DRG 850
MetricFY2026FY2027Change
Relative weight8.65908.4080-0.2510
Geometric mean LOS (days)15.315.6+0.3
Arithmetic mean LOS (days)23.023.2+0.2
Weights shown are the FY2027 final values after the 10% cap on year-over-year reductions where applicable.

CC and MCC family

DRG 850 stands alone: CMS does not split this base group by CC or MCC severity, so complication documentation does not move the assignment, although it still affects quality and risk-adjustment reporting.

Grouper logic (v44 Definitions Manual)

Principal Diagnosis: 33 ICD-10 codes drive assignment to this group; the first 12 are shown.

Principal Diagnosis codes assigned to DRG 850 (sample)
ICD-10 codeDescription
C9100Acute lymphoblastic leukemia not having achieved remission
C9101Acute lymphoblastic leukemia, in remission
C9102Acute lymphoblastic leukemia, in relapse
C9200Acute myeloblastic leukemia, not having achieved remission
C9201Acute myeloblastic leukemia, in remission
C9202Acute myeloblastic leukemia, in relapse
C9240Acute promyelocytic leukemia, not having achieved remission
C9241Acute promyelocytic leukemia, in remission
C9242Acute promyelocytic leukemia, in relapse
C9250Acute myelomonocytic leukemia, not having achieved remission
C9251Acute myelomonocytic leukemia, in remission
C9252Acute myelomonocytic leukemia, in relapse

Documentation and denial exposure

As a surgical DRG, assignment depends on a qualifying operating-room procedure being coded from the operative report; a missing or non-OR procedure code drops the stay into a medical DRG in MDC 17 with a lower weight. Because this family has no severity split, review risk concentrates on medical-necessity of the admission itself and on the two-midnight benchmark. Typical inpatient denial codes for this group: CARC 16 (claim lacks information needed to group the stay), CARC 50 (the admission or procedure is judged not medically necessary), CARC 97 (a service is bundled into the DRG payment).

How QuickIntell uses DRG 850 data

QuickCode groups inpatient encounters against the current v44 logic, flags CC and MCC candidates that lack supporting documentation, and shows the weight difference across the family before the claim drops. QuickScribe captures the attending's language that supports severity, and QuickRCM works DRG-validation denials with the grouper evidence attached.

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Frequently asked questions — DRG 850

What is MS-DRG 850?

MS-DRG 850 is "Acute Leukemia with Other Procedures", a surgical Medicare Severity Diagnosis-Related Group in MDC 17, Myeloproliferative Diseases and Disorders, Poorly Differentiated Neoplasms. Medicare pays inpatient stays grouped here at the hospital's base rate multiplied by the DRG relative weight.

What is the FY2027 relative weight for DRG 850?

The FY2027 relative weight is 8.4080 (IPPS final rule Table 5, effective October 1, 2026). In FY2026 it was 8.6590, a change of -2.9%.

What is the average length of stay for DRG 850?

CMS reports a geometric mean length of stay of 15.6 days and an arithmetic mean of 23.2 days for FY2027. The geometric mean is used for transfer-payment calculations.

What documentation supports the severity level of DRG 850?

DRG 850 has no CC or MCC sibling, so secondary-diagnosis capture does not change the group or its weight. Review effort belongs instead on the principal diagnosis sequencing and the procedure codes that place the stay in this group, and on medical necessity of the inpatient admission itself under the two-midnight benchmark, which is where denials for single-severity groups concentrate.

Which codes group to DRG 850?

The v44 Definitions Manual lists 33 principal diagnosis codes for this group. Examples from the principal diagnosis list: C9100 (Acute lymphoblastic leukemia not having achieved remission); C9101 (Acute lymphoblastic leukemia, in remission); C9102 (Acute lymphoblastic leukemia, in relapse); C9200 (Acute myeloblastic leukemia, not having achieved remission).

Is DRG 850 a post-acute transfer DRG?

No. DRG 850 is not on the FY2027 post-acute care transfer list, so the transfer per-diem policy does not apply to it.

Sources

Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-01. Verify against the primary file before billing or contracting decisions.

Disclaimer

This page is an operational reference compiled from the CMS IPPS FY2027 final rule (Table 5) and the v44 ICD-10 MS-DRG Definitions Manual. Relative weights are national factors; actual payment depends on each hospital's wage-adjusted base rate, add-ons, outliers and transfer adjustments. Nothing here is legal, clinical or billing advice; verify grouping against your encoder and the published CMS files.