REPRODUCIBILITY OF FINE-NEEDLE ASPIRATION BIOPSY IN THE DIAGNOSIS OF ACUTE REJECTION OF RENAL-ALLOGRAFTS

Background. Although it has been used as a diagnostic tool in many ren al transplant centres the reproducibility of fine-needle aspiration bi opsy (FNAB) has not been critically evaluated. Methods. In the present study material sequentially obtained from 15 patients (177 aspiration s) over a 3-month period following renal transplantation was evaluated by two independent observers. Intraobserver reproducibility was studi ed through the analysis of two evaluations by observer 1 performed 8 m onths apart. Interobserver reproducibility was calculated comparing th e second evaluation of observer 1 with the evaluation of observer 2. A ll evaluations were performed blindly. Slides and protocols of individ ual patients were chronologically arranged and thus interpreted. Repre sentation, total corrected increment (TCI), accuracy, and the percent agreement for the diagnosis of acute rejection were evaluated. Results . No intraobserver statistically significant differences were observed . Differences observed in interobserver evaluation of TCI either durin g, or out of acute rejection episodes, well as the representative qual ity of the sample and accuracy, were not statistically significant. Th e percent of agreement for the presence or absence of acute rejection was 77.5% for the intraobserver comparison and 76.7% for the interobse rver evaluation. Both values showing either a non-significant value fo r the difference or a statistical significance for the concordance. Co nclusion. We concluded that FNAB is an accurate method with fairly goo d intra- and interobserver reproducibility for the diagnosis of acute rejection of renal allografts.