Use of C-Reactive Protein as a Diagnostic Tool for Early Detection of Bacterial Infection After Liver Transplantation

C-reactive protein (CRP) evaluation in human urine using optical sensor supported by machine learning

The rapid and sensitive indicator of inflammation in the human body is C-Reactive Protein (CRP). Determination of CRP level is important in medical diagnostics because, depending on that factor, it may indicate, e.g., the occurrence of inflammation of various origins, oncological, cardiovascular, bacterial or viral events. In this study, we describe an interferometric sensor able to detect the CRP level for distinguishing between no-inflammation and inflammation states. The measurement head was made of a single mode optical fiber with a microsphere structure created at the tip. Its surface has been biofunctionalized for specific CRP bonding. Standardized CRP solutions were measured in the range of 1.9 µg/L to 333 mg/L and classified in the initial phase of the study. The real samples obtained from hospitalized patients with diagnosed Urinary Tract Infection or Urosepsis were then investigated. 27 machine learning classifiers were tested for labeling the phantom samples as normal or high CRP levels. With the use of the ExtraTreesClassifier we obtained an accuracy of 95% for the validation dataset. The results of real samples classification showed up to 100% accuracy for the validation dataset using XGB classifier.

Applicability of common inflammatory markers in diagnosing infections in early period after liver transplantation in intensive care setting

Infections remain an important cause of morbidity and mortality early after liver transplantation. The aim of this prospective longitudinal study was to evaluate clinical utility of c-reactive protein (CRP), procalcitonin, and neutrophil-to-lymphocyte ratio (NLR) in surveillance of infections early after liver transplantation in intensive care setting. A total of 60 liver transplant recipients were included. CRP, procalcitonin, and NLR assessed at 12-hour intervals were primary variables of interest. Infections and severe complications during postoperative intensive care unit stay were the primary and secondary end-points, respectively. Infections and severe complications were diagnosed in 9 and 17 patients, respectively. Only peak CRP beyond first 48 hours was associated with infections (p = 0.038) with AUC, positive and negative predictive value of 0.728, 42.9% and 92.2%, respectively (cut-off: 142.7 mg/L). Peak procalcitonin over first 60 hours was the earliest predictor (p = 0.050) of severe complications with AUC, positive and negative predictive value of 0.640, 53.3% and 80.0%, respectively (cut-off: 42.8 ng/mL). In conclusion, while CRP, procalcitonin, and NLR cannot be used for accurate diagnosis of infections immediately after liver transplantation, peak CRP beyond 48 hours and peak procalcitonin over first 60 hours may be used for initial exclusion of infections and prediction of severe complications, respectively.