Hepatology, Organ Transplant Allocation & Clinical Scoring
UNOS MELD Liver Transplant Allocation Score Formula
Calculate Original UNOS Model for End-Stage Liver Disease (MELD) Score 9.57*LN(Cr_eff) + 3.78*LN(Bili_eff) + 11.2*LN(INR_eff) + 6.43 with mandatory 1.0 lower lab floors, 4.0 Creatinine/Dialysis ceiling, and [6, 40] clamping.
Enforce UNOS 1.0 lab floors and the 4.0 dialysis ceiling before taking natural logarithms!
Coding the Model for End-Stage Liver Disease (MELD, Kamath et al. 2001) into a clinical research spreadsheet without UNOS Policy 9.1 boundary clamps produces dangerously wrong scores: any lab value below 1.0 (e.g., Serum Creatinine 0.7 mg/dL or Bilirubin 0.6 mg/dL) has a NEGATIVE natural logarithm LN(x) < 0 that artificially subtracts points from a critically coagulopathic patient! Official UNOS MELD rules enforce four exact clamps: (1) floor Creatinine, Total Bilirubin, and INR at MAX(1.0, value); (2) cap Creatinine at MIN(4.0, Cr)—and set Effective Creatinine = 4.0 automatically if the patient required >= 2 dialysis sessions (or 24h CVVHD) in the prior week; (3) evaluate 9.57 * LN(Cr_eff) + 3.78 * LN(Bili_eff) + 11.2 * LN(INR_eff) + 6.43; and (4) round to the nearest integer clamped within [6, 40]!
Verify on a Decompensated Cirrhosis Patient—Serum_Creatinine = 2.0 mg/dL (B2), Total_Bilirubin = 4.0 mg/dL (B3), Prothrombin_INR = 2.0 (B4), and Twice_Weekly_Dialysis_Flag = 0 (B5 -> Effective Creatinine = 2.00 mg/dL in E2): Unrounded MELD is 9.57*LN(2) + 3.78*LN(4) + 11.2*LN(2) + 6.43 = 6.633 + 5.240 + 7.763 + 6.430 = 26.07 (E3); Official UNOS Integer MELD is 26 (E4); placing the candidate in "High Urgency Allocation (MELD >= 25)" (E5)!
| UNOS MELD Allocation Metric (Cr=2.0, Bilirubin=4.0, INR=2.0, Dialysis=0) | Formula | Verified Output |
|---|---|---|
| UNOS Effective Creatinine (mg/dL) | IF(Dialysis=1, 4, MIN(4, MAX(1, Cr))) | 2.00 mg/dL (4.00 @ Dialysis=1) |
| Continuous MELD Raw Score | 9.57*LN(Cr) + 3.78*LN(Bili) + 11.2*LN(INR) + 6.43 | 26.07 (6.43 @ Normal <1.0 Labs) |
| Official UNOS Integer MELD [6–40] | MIN(40, MAX(6, ROUND(Raw_MELD, 0))) | 26 (33 @ Dialysis=1; 6 Floor) |
| Hepatology Transplant Urgency | >=25 High | 15–24 Mod | <15 Low | High Urgency Allocation (MELD >= 25) |
Official UNOS Clamped Integer MELD [6, 40] Formula
Validate strictly positive lab values Cr, Bilirubin, INR > 0 and binary Dialysis_Flag in {0, 1}!
=LET(cr_v, B2, bl_v, B3, in_r, B4, dl_f, B5, IF(OR(cr_v <= 0, bl_v <= 0, in_r <= 0, AND(dl_f <> 0, dl_f <> 1)), "Invalid Hepatology Lab Input", LET(cr_e, IF(dl_f = 1, 4, MIN(4, MAX(1, cr_v))), bl_e, MAX(1, bl_v), in_e, MAX(1, in_r), rw_m, 9.57 * LN(cr_e) + 3.78 * LN(bl_e) + 11.2 * LN(in_e) + 6.43, MIN(40, MAX(6, ROUND(rw_m, 0))))))Dialysis 4.0 Ceiling (MELD 33) & Sub-1.0 Normal-Lab Floor (MELD 6) Checks
Set Dialysis_Flag B5 = 1: Effective Creatinine jumps to 4.0 mg/dL and UNOS MELD E4 rises from 26 to 33! Or enter normal sub-unity labs B2 = 0.7, B3 = 0.6, B4 = 0.9, B5 = 0: MAX(1, ...) zeroes all three logs, clamping MELD cleanly at 6!
=IF(ISTEXT(E4), E4, IF(E4 >= 25, "High Urgency Allocation (MELD >= 25)", IF(E4 >= 15, "Moderate Transplant Benefit (15-24)", "Low Urgency Monitoring (< 15)")))Try the example
Use the original values or change them to test your understanding.