The Tacrolimus Level (Tacrolimus, or Tacrolimus Level) test in blood using High-Performance Liquid Chromatography coupled with Tandem Mass Spectrometry (HPLC-MS/MS) is a laboratory test used to monitor the levels of this immunosuppressive drug. Tacrolimus is one of the key medications used to prevent organ rejection after transplantation, particularly in kidney and liver transplants. This advanced technique allows for highly accurate measurement of Tacrolimus levels, enabling physicians to adjust drug doses according to each patient’s needs. Maintaining an appropriate Tacrolimus level is essential to ensure treatment effectiveness and reduce the risk of potential side effects, such as infections or organ damage. The test is performed by drawing a blood sample, which is a safe and quick procedure. The results are used to guide therapy and ensure proper patient care, helping to improve transplant outcomes and enhance quality of life.