Key facts for DRG 173
- FY2027 relative weight
- 2.9550
- Higher than 77% of all MS-DRGs
- Change vs FY2026
- -0.7%
- FY2026 weight 2.9760
- Geometric mean LOS
- 3.7 days
- Arithmetic mean 4.5 days
- MDC
- 04
- Assignment of Diagnosis Codes
- Severity level
- single severity level
- Transfer policy
- Not a transfer DRG
TL;DR
MS-DRG 173 is a surgical group in MDC 04 (Assignment of Diagnosis Codes) at a single-severity group of its family. CMS assigns it a FY2027 relative weight of 2.9550 with a geometric mean length of stay of 3.7 days and an arithmetic mean of 4.5. Its weight moved down 0.7% from FY2026 (2.9760). That weight is higher than 77% of all surgical and medical MS-DRGs. CMS does not split this group by severity. The v44 Definitions Manual assigns it through 13 principal diagnosis codes and 10 and operating room procedures codes.
What changed from FY2026 to FY2027
CMS recalibrates every MS-DRG weight annually from the prior year's MedPAR claims. For DRG 173 the FY2027 relative weight is 2.9550 against 2.9760 in FY2026, a fall of 0.71%.
| Metric | FY2026 | FY2027 | Change |
|---|---|---|---|
| Relative weight | 2.9760 | 2.9550 | -0.0210 |
| Geometric mean LOS (days) | 3.8 | 3.7 | -0.1 |
| Arithmetic mean LOS (days) | 4.6 | 4.5 | -0.1 |
CC and MCC family
DRG 173 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: 13 ICD-10 codes drive assignment to this group; the first 12 are shown.
| ICD-10 code | Description |
|---|---|
| I2601 | Septic pulmonary embolism with acute cor pulmonale |
| I2602 | Saddle embolus of pulmonary artery with acute cor pulmonale |
| I2603 | Cement embolism of pulmonary artery with acute cor pulmonale |
| I2604 | Fat embolism of pulmonary artery with acute cor pulmonale |
| I2609 | Other pulmonary embolism with acute cor pulmonale |
| I2690 | Septic pulmonary embolism without acute cor pulmonale |
| I2692 | Saddle embolus of pulmonary artery without acute cor pulmonale |
| I2693 | Single subsegmental thrombotic pulmonary embolism without acute cor pulmonale |
| I2694 | Multiple subsegmental thrombotic pulmonary emboli without acute cor pulmonale |
| I2695 | Cement embolism of pulmonary artery without acute cor pulmonale |
| I2696 | Fat embolism of pulmonary artery without acute cor pulmonale |
| I2699 | Other pulmonary embolism without acute cor pulmonale |
And Operating Room Procedures: 10 ICD-10 codes drive assignment to this group.
| ICD-10 code | Description |
|---|---|
| 02FP3Z0 | Fragmentation of Pulmonary Trunk, Percutaneous Approach, Ultrasonic |
| 02FP3ZZ | Fragmentation of Pulmonary Trunk, Percutaneous Approach |
| 02FQ3Z0 | Fragmentation of Right Pulmonary Artery, Percutaneous Approach, Ultrasonic |
| 02FQ3ZZ | Fragmentation of Right Pulmonary Artery, Percutaneous Approach |
| 02FR3Z0 | Fragmentation of Left Pulmonary Artery, Percutaneous Approach, Ultrasonic |
| 02FR3ZZ | Fragmentation of Left Pulmonary Artery, Percutaneous Approach |
| 02FS3Z0 | Fragmentation of Right Pulmonary Vein, Percutaneous Approach, Ultrasonic |
| 02FS3ZZ | Fragmentation of Right Pulmonary Vein, Percutaneous Approach |
| 02FT3Z0 | Fragmentation of Left Pulmonary Vein, Percutaneous Approach, Ultrasonic |
| 02FT3ZZ | Fragmentation of Left Pulmonary Vein, Percutaneous Approach |
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 04 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 173 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.
Frequently asked questions — DRG 173
What is MS-DRG 173?
MS-DRG 173 is "Ultrasound Accelerated and Other Thrombolysis with Principal Diagnosis Pulmonary Embolism", a surgical Medicare Severity Diagnosis-Related Group in MDC 04, Assignment of Diagnosis Codes. 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 173?
The FY2027 relative weight is 2.9550 (IPPS final rule Table 5, effective October 1, 2026). In FY2026 it was 2.9760, a change of -0.7%.
What is the average length of stay for DRG 173?
CMS reports a geometric mean length of stay of 3.7 days and an arithmetic mean of 4.5 days for FY2027. The geometric mean is used for transfer-payment calculations.
What documentation supports the severity level of DRG 173?
DRG 173 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 173?
The v44 Definitions Manual lists 13 principal diagnosis codes and 10 and operating room procedures codes for this group. Examples from the principal diagnosis list: I2601 (Septic pulmonary embolism with acute cor pulmonale); I2602 (Saddle embolus of pulmonary artery with acute cor pulmonale); I2603 (Cement embolism of pulmonary artery with acute cor pulmonale); I2604 (Fat embolism of pulmonary artery with acute cor pulmonale).
Is DRG 173 a post-acute transfer DRG?
No. DRG 173 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.
- IPPS FY2027 Final Rule Table 5 (CMS-1849-F)Version v44 FY2027 · effective 2026-10-01 · file CMS-1849-F Table 5.txtSHA-256 01003dd571c1e2f5…
- IPPS FY2026 Final Rule Table 5 (CMS-1833-F)Version v43 FY2026 · effective 2025-10-01 · file CMS-1833-F Table 5.txtSHA-256 bf8c390d14b3cd3e…
- ICD-10 MS-DRG Definitions Manual v44 (text)Version v44 · effective 2026-10-01 · file fy2027-fr-icd10-ms-drg-definitions-manual-files-v44.zipSHA-256 ae4f6c11727fe91f…
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.