9341. Tacrolimus

A tacrolimus test determines the level of this immunosuppressive medication in the blood. Tacrolimus is used to prevent rejection of transplanted organs and to treat certain autoimmune diseases. Regular monitoring of the drug level helps the physician maintain an effective concentration while minimizing the risk of adverse effects.

Tacrolimus is a potent immunosuppressant used to prevent rejection of transplanted organs (kidneys, liver, heart, and lungs) and to treat certain autoimmune diseases.

Blood tacrolimus level testing is prescribed exclusively for patients receiving treatment with this medication. The main purposes of the test are:

• prevention of transplant rejection (after organ transplantation, maintaining a certain tacrolimus level is critical to prevent activation of the immune system and an immune attack on the transplanted organ);
• monitoring the therapeutic concentration (tacrolimus has a narrow therapeutic range, meaning there is only a small difference between an effective concentration and a level that may cause adverse effects, such as nephrotoxicity, neurotoxicity, hypertension, and tremor. Regular monitoring of the drug level in the blood allows the physician to maintain an optimal balance between treatment efficacy and safety);
• dose adjustment (test results help the physician individually select and adjust the tacrolimus dose to achieve the target therapeutic range. Target levels may vary depending on the type of transplant, time since surgery, concomitant immunosuppressive therapy, and the patient's clinical condition—for example, higher levels may be required during the first months after transplantation than later);
• assessment of compliance (treatment adherence) (regular measurements of tacrolimus levels can help the physician assess how closely the patient follows the prescribed treatment regimen);
• detection of interactions with other medications (many medications can affect tacrolimus metabolism, increasing or decreasing its blood level. Regular monitoring helps identify such interactions and adjust the dose of tacrolimus or concomitant medications);
• monitoring changes in the patient's condition (changes in liver or kidney function, or the development of other diseases, may affect tacrolimus levels in the blood and require more frequent monitoring).

• To determine the blood concentration of the drug (in case of a change in the dosage or dosage form of the medication).
• To determine and adjust the individual dose of the medication (if non-compliance with the prescribed dosing regimen is suspected).
• In cases of suspected drug overdose.
• To monitor tacrolimus blood concentration after transplantation (to optimize treatment control through dose adjustment).
• In the event of symptoms of intoxication or adverse effects during treatment.

• Venous blood

In order to exclude factors that may affect the test results, we recommend to follow the preparation rules: