Healthcare Revenue Cycle & Hospital Finance
Hospital MS-DRG & High-Cost Outlier Payment Formula
Calculate CMS Inpatient Prospective Payment System (IPPS) Base MS-DRG Reimbursement, Cost-to-Charge Ratio (CCR) Estimated Case Cost, 80% High-Cost Outlier Add-On, and Total Claim Payment.
Deflate hospital chargemaster bills by CCR before testing CMS outlier stop-loss!
Under the Medicare Inpatient Prospective Payment System (IPPS), acute-care hospitals receive a fixed diagnosis-related bundle Base_DRG = Standardized_Base_Rate * MS_DRG_Weight regardless of actual length of stay—EXCEPT on catastrophic ICU/surgical cases that breach the annual CMS Fixed-Loss Outlier Threshold! Crucially, CMS NEVER compares raw chargemaster Billed_Charges directly against the outlier threshold: first, billed charges are deflated to Estimated_Case_Cost = Billed_Charges * Hospital_CCR (using the hospital’s Medicare Cost-to-Charge Ratio), and then CMS reimburses 80% of costs exceeding Base_DRG + Fixed_Loss_Stop (90% for burn MS-DRGs): Outlier_Addon = 0.80 * MAX(0, Estimated_Case_Cost - (Base_DRG + Fixed_Loss_Stop))!
Verify on Hospital_Base_Rate = $7,000 (B2), Surgical_MS_DRG_Weight = 2.50 (B3 -> Base MS-DRG Payment = $17,500.00 in E2), Gross_Billed_Charges = $250,000 (B4), Medicare_CCR = 0.30 (30.0%, B5 -> Estimated Case Cost = $75,000.00 in E3), and CMS_Fixed_Loss_Threshold = $42,500 (B6 -> Stop-Loss Attachment = $17,500 + $42,500 = $60,000): Excess Cost above attachment is $75,000 - $60,000 = $15,000, generating an 80% Outlier Add-On of $12,000.00 (E4) and Total IPPS Reimbursement of $29,500.00 (E5)! On a routine $120,000 chargemaster stay (Cost = $36,000 < $60,000), Outlier Add-On is $0.00 and Total Payment stays capped at $17,500.00!
| CMS IPPS Outlier Metric (Base=$7k, Wt=2.50, Charges=$250k, CCR=0.30, Stop=$42.5k) | Formula | Verified Output |
|---|---|---|
| Base MS-DRG Bundle Payment ($) | Hospital_Base_Rate * DRG_Weight | $17,500.00 |
| CCR-Deflated Case Cost ($) | Billed_Charges * Hospital_CCR | $75,000.00 ($60k Outlier Stop) |
| 80% High-Cost Outlier Add-On ($) | 0.80 * MAX(0, Case_Cost - (Base + Stop)) | $12,000.00 ($0 @ $120k Charges) |
| Total IPPS Claim Reimbursement ($) | Base_DRG + Outlier_Addon | $29,500.00 |
CMS IPPS Base MS-DRG + 80% Outlier Payment Formula
Validate Base_Rate > 0, DRG_Weight > 0, Billed_Charges >= 0, 0 < CCR <= 1, and Fixed_Loss_Stop > 0!
=LET(bs_r, B2, dr_w, B3, ch_g, B4, cc_r, B5, fl_s, B6, IF(OR(bs_r <= 0, dr_w <= 0, ch_g < 0, cc_r <= 0, cc_r > 1, fl_s <= 0), "Invalid IPPS Claim", LET(bs_p, bs_r * dr_w, cs_e, ch_g * cc_r, ot_p, 0.8 * MAX(0, cs_e - (bs_p + fl_s)), ROUND(bs_p + ot_p, 2))))Standalone High-Cost Outlier Add-On Audit Formula
When revenue-integrity analysts ask the in-app assistant for a hint on why an ICU claim missed outlier status, check whether chargemaster markup lowered CCR (B5) so B4 * B5 stayed below E2 + B6!
=IF(ISTEXT(E2), E2, ROUND(0.8 * MAX(0, (B4 * B5) - (E2 + B6)), 2))Try the example
Use the original values or change them to test your understanding.