Tacrolimus by Tandem Mass Spectrometry

Casandra

Casandra Test Code AR95168Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 0090612CPT Code 80197

Tacrolimus by Tandem Mass Spectrometry

Also known as: TACRO

Clinical Use

Order Test

Use

The test is used to optimize dosing of tacrolimus, a critical immunosuppressant drug, and monitor patient adherence in transplant recipients. Therapeutic drug monitoring is essential due to tacrolimus's narrow therapeutic range and variable pharmacokinetics, which necessitates personalized dosing to achieve desired therapeutic effects while minimizing toxicity. This test provides quantitative determination of tacrolimus concentration in whole blood, aiding in the management of kidney, heart, and liver transplant patients among others.

Special Instructions

Tacrolimus whole blood concentrations can be measured by either chromatographic or immunoassay methodologies, which are not directly interchangeable. The measured concentration depends on the methodology used, with immunoassays often showing a positive bias due to antibody cross-reactivity with metabolites. Therefore, consistency in the method used for monitoring is crucial to ensure accurate dosing adjustments.

Limitations

The therapeutic range provided is a guideline, and the optimal therapeutic range for an individual patient may differ based on the indication for therapy, treatment phase, use with other drugs, timing of specimen collection, type of transplanted organ, and therapeutic approach of the transplant center. The test has not been cleared or approved by the US FDA but is developed in a CLIA certified laboratory for clinical purposes.

Test Details

New York Approved