Predicting long-term outcome in renal transplantation.

Long-term outcome in renal transplantation is heterogeneous, and predicting success is challenging. Astor and colleagues report that serum β2M levels measured on discharge after transplantation correlate closely with long-term patient and graft survival, and may serve as a biomarker of clinical risk. β2M may provide a more precise measurement of glomerular filtration, combined with an index of inflammatory burden related to rejection or systemic vascular disease. Association must not be confused with prediction, however, and the role of β2M must be tested in a validation cohort to define sensitivity, specificity and predictive performance at the individual, rather than the population, level.