Guida all'uso clinico dei biomarcatori in oncologia: Metodi di misura e interpretazione

Currently available tumour markers are generally determined by immunoassays. The performance of immunoassays is therefore examined, focusing on flaws that may affect the accuracy of measurements. The use of international reference preparations, IQC and EQA programs are also discussed, focusing on their role in reducing and/or managing imprecision and bias. The diagnostic performance is examined, by defining and discussing sensitivity, specificity, ROC curve analysis, positive and negative predictive values, and likelihood ratio. The difference between sensitivity and positive predictive value is examined in detail with reference to different clinical scenarios characterized by different prevalence of malignancy. The interpretative approaches to be used when serial biomarker measurements are available are also discussed, highlighting their potential usefulness as well as their limitations. Finally, the principles of economic evaluation of diagnostic tests are provided and the phases of the evaluation process are described in detail. The deficiency of economic evaluations on the use of circulating tumour markers ascertained in currently available guidelines is highlighted.