Specific laboratory methodologies achieve higher model for endstage liver disease (MELD) scores for patients listed for liver transplantation

Abstract

Priority for liver transplantation is currently based on the Model for Endstage Liver Disease (MELD) score, a mathematical function which includes the following objective variables: bilirubin, creatinine (Cr), and international normalized ratio (INR). We have noted that specific laboratory methodologies may yield consistently higher values of bilirubin, Cr, and INR. Therefore, we performed a study to determine if higher MELD scores could be obtained by utilizing laboratory methodologies selected to return higher laboratory values than standard methodologies used in our hospital's clinical laboratory. Phlebotomy was performed for routine clinical indications in 29 consecutive patients listed for liver transplantation. MELD scores were calculated using bilirubin, Cr, and INR from laboratory methods in our hospital's clinical laboratory (designated Lab #1) and from 2 other clinical laboratories (designated Lab #2 and Lab #3). The mean MELD score in our hospital's clinical laboratory (Lab #1) (13.6) was not significantly different than in Lab #2 (14.7), but in Lab #3, it was significantly higher by 20% (17.1), P <.03. Virtually all of the difference in MELD score between our hospital's clinical laboratory (Lab #1) and Lab #3 could be attributed to the INR, which was significantly higher by 26% in Lab #3 (1.9) vs. Lab #1 (1.4), P <.00002. Using MELD scores calculated from our hospital's clinical laboratory, the average change in priority for liver transplantation was from the 58th percentile to the 77th percentile (compared to Lab #3), P =.01. In conclusion, patients listed for liver transplantation at our center achieved significantly higher MELD scores and therefore a higher priority for liver transplantation by using laboratory methodologies that yield higher INR values than our hospital laboratory. The selection of laboratory methodologies may have a significant impact on MELD score.