Correlation Between Tacrolimus Levels in Blood Samples Obtained from Central Catheter and Peripheral Venipuncture in Lung Transplant Patients (Ven-Cat Study).

Background: Following lung transplantation (LT), receiving immunosuppressive therapy is crucial. Tacrolimus is considered a drug with a narrow therapeutic range and its use requires constant monitoring. This study aimed to evaluate the correlation between tacrolimus levels obtained from central venous catheter and direct venipuncture in adult patients undergoing LT.

Methods: This prospective study included LT patients hospitalized in conventional ward carrying a central catheter through which no intravenous tacrolimus was administered. Trough samples were obtained through direct puncture and from the central catheter. Pearson correlation coefficient was calculated to quantify the mean difference between the 2 measures.

Results: A total of 54 sample pairs from 16 LT patients were obtained, mostly male (81.3%) and bilateral transplant recipients (93.8%); the transplant procedure was the primary reason for admission (81.3%). The difference in tacrolimus levels between both samples was 0.3 (0.1-0.6) mcg/L, with the measurement for the samples obtained through venipuncture being mostly higher than that for those obtained from the catheter. A strong correlation was observed between the tacrolimus levels in the samples obtained from the catheter and through venipuncture (Pearson correlation coefficient, 0.991; P < 0.001; R2 = 0.982).

Conclusions: There is an excellent correlation between tacrolimus levels obtained from venipuncture and those obtained from central venous catheter in LT patients undergoing oral tacrolimus therapy.