Is calculating the standard deviation of tacrolimus blood levels the new gold standard for evaluating non-adherence to medications in transplant recipients?

No it is not. Not yet. But looking at blood level variation might – in the near future - indeed become the de-facto gold standard for assessment of nonadherence in the transplant setting. If it does, this measurement method could lead to important discoveries not only for the transplant field but for adherence and outcomes research in other areas of medicine as well. Since nonadherence accounts for a majority of late rejections in pediatric solid organ transplant recipients (1–3), the discovery of a useful measure of adherence could be of great clinical importance in the provision of posttransplant care.