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Utility of icteric index in clinical laboratories: more than a preanalytical indicator

INTRODUCTION: Total bilirubin tests are highly demanded in clinical laboratories. Since icteric index (I-index) has zero cost, we aimed to evaluate its clinical utility and cost-effectiveness to determine if total bilirubin is necessary to be tested. We took into account if haemolysis could interfer...

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Autores principales: Mondejar, Rufino, Mayor Reyes, María, Melguizo Madrid, Enrique, Cañavate Solano, Consuelo, Pérez Ramos, Santiago
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Croatian Society of Medical Biochemistry and Laboratory Medicine 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8047785/
https://www.ncbi.nlm.nih.gov/pubmed/33927553
http://dx.doi.org/10.11613/BM.2021.020703
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author Mondejar, Rufino
Mayor Reyes, María
Melguizo Madrid, Enrique
Cañavate Solano, Consuelo
Pérez Ramos, Santiago
author_facet Mondejar, Rufino
Mayor Reyes, María
Melguizo Madrid, Enrique
Cañavate Solano, Consuelo
Pérez Ramos, Santiago
author_sort Mondejar, Rufino
collection PubMed
description INTRODUCTION: Total bilirubin tests are highly demanded in clinical laboratories. Since icteric index (I-index) has zero cost, we aimed to evaluate its clinical utility and cost-effectiveness to determine if total bilirubin is necessary to be tested. We took into account if haemolysis could interfere to icteric index determination. MATERIAL AND METHODS: Retrospectively we reviewed I-index results in two cohorts (43,372 and 8507 non-haemolysed and haemolysed samples, respectively). All determinations were done using Alinity c chemistry analysers (Abbott Diagnostics). Receiver operating characteristic (ROC) curve was used to determine the optimal index cut-off to discriminate between normal and abnormal bilirubin concentration (20.5 µmol/L). RESULTS: The ROC curve analysis suggested 21.4 µmol/L as the optimal I-index cut-off but differences in sensitivity and specificity were detected between patient derivation. For rejecting purpose, 15.4 µmol/L and 17.1 µmol/L I-index thresholds were selected based on patient derivation (inpatients and emergency room; and primary care and outpatients, respectively) with 97% sensitivity and 0.25% false negative results. Sensitivity was much lower in haemolysed samples. We selected 34.2 µmol/L I-index as threshold to detect hyperbilirubinemia with 99.7% specificity and 0.26% false positive results, independent of haemolysis. With the icteric index cut-offs proposed, we would save 66% of total bilirubin requested and analyse total bilirubin in around 2% of samples without total bilirubin requested. CONCLUSIONS: This study supports the use of I-index to avoid bilirubin determination and to identify patients with hyperbilirubinemia. This work considers that the economic and test savings could help to increase the efficiency in clinical laboratories.
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spelling pubmed-80477852021-04-28 Utility of icteric index in clinical laboratories: more than a preanalytical indicator Mondejar, Rufino Mayor Reyes, María Melguizo Madrid, Enrique Cañavate Solano, Consuelo Pérez Ramos, Santiago Biochem Med (Zagreb) Original Articles INTRODUCTION: Total bilirubin tests are highly demanded in clinical laboratories. Since icteric index (I-index) has zero cost, we aimed to evaluate its clinical utility and cost-effectiveness to determine if total bilirubin is necessary to be tested. We took into account if haemolysis could interfere to icteric index determination. MATERIAL AND METHODS: Retrospectively we reviewed I-index results in two cohorts (43,372 and 8507 non-haemolysed and haemolysed samples, respectively). All determinations were done using Alinity c chemistry analysers (Abbott Diagnostics). Receiver operating characteristic (ROC) curve was used to determine the optimal index cut-off to discriminate between normal and abnormal bilirubin concentration (20.5 µmol/L). RESULTS: The ROC curve analysis suggested 21.4 µmol/L as the optimal I-index cut-off but differences in sensitivity and specificity were detected between patient derivation. For rejecting purpose, 15.4 µmol/L and 17.1 µmol/L I-index thresholds were selected based on patient derivation (inpatients and emergency room; and primary care and outpatients, respectively) with 97% sensitivity and 0.25% false negative results. Sensitivity was much lower in haemolysed samples. We selected 34.2 µmol/L I-index as threshold to detect hyperbilirubinemia with 99.7% specificity and 0.26% false positive results, independent of haemolysis. With the icteric index cut-offs proposed, we would save 66% of total bilirubin requested and analyse total bilirubin in around 2% of samples without total bilirubin requested. CONCLUSIONS: This study supports the use of I-index to avoid bilirubin determination and to identify patients with hyperbilirubinemia. This work considers that the economic and test savings could help to increase the efficiency in clinical laboratories. Croatian Society of Medical Biochemistry and Laboratory Medicine 2021-04-15 2021-06-15 /pmc/articles/PMC8047785/ /pubmed/33927553 http://dx.doi.org/10.11613/BM.2021.020703 Text en Croatian Society of Medical Biochemistry and Laboratory Medicine. https://creativecommons.org/licenses/by/4.0/This is an Open Access article distributed under the terms of the Creative Commons Attribution (http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) ) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Original Articles
Mondejar, Rufino
Mayor Reyes, María
Melguizo Madrid, Enrique
Cañavate Solano, Consuelo
Pérez Ramos, Santiago
Utility of icteric index in clinical laboratories: more than a preanalytical indicator
title Utility of icteric index in clinical laboratories: more than a preanalytical indicator
title_full Utility of icteric index in clinical laboratories: more than a preanalytical indicator
title_fullStr Utility of icteric index in clinical laboratories: more than a preanalytical indicator
title_full_unstemmed Utility of icteric index in clinical laboratories: more than a preanalytical indicator
title_short Utility of icteric index in clinical laboratories: more than a preanalytical indicator
title_sort utility of icteric index in clinical laboratories: more than a preanalytical indicator
topic Original Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8047785/
https://www.ncbi.nlm.nih.gov/pubmed/33927553
http://dx.doi.org/10.11613/BM.2021.020703
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