Biomarkers and clinical significance

Biomarkers are measures taken from blood or other biological material or physiological measurement. Biomarkers include genetic variations, protein levels, and measures of brain activity among others. It is hoped that biomarkers can help predict outcomes in depression and select treatments that are more likely to work for a given individual. This is called personalized medicine. However, for a biomarker to be clinically meaningful it has to predict a difference in outcomes that is noticeable and really makes difference to the affected individual. This means that the prediction has to be strong enough to be clinically significant. Clinical significance should be distinguished from statistical significance. Statistical significance means that an effect is unlikely to be due to chance alone and depends on effect size, distribution of the biomarker and sample size. Clinical significance means that an effect can make a difference for an individual patient and it depends mainly on effect size. If you would like to estimate whether a biomarker predicting outcome of depression treatment is likely to be clinically significant, please go to the clinical significance calculator.