A-104 Study of the matrix effect for thyroglobulin and calcitonin in fine-needle aspiration of cervical nodules

Background Analysis of material from fine needle aspiration of cervical thyroglobulin nodules with Beckman Coulter reagents on the ACCESS equipment and Calcitonin using the Siemens reagent on the Immulite equipment. The matrix effect, linearity and the limit of analytical sensitivity were analyzed. This study aims to analyze the correlation between the serum/plasma results described in the suppliers' package inserts with the results obtained with the puncture matrix. Methods The performance characteristics were tested according to the laboratory's operating procedures, based on the recommendations of ANVISA RDC 166/2017. Such parameters involved doping, which corresponds to the introduction of a calibrator with a known and traceable value into a pool of puncture material that is known to be negative, in order to analyze the behavior of the results obtained, paying attention to the deviations that may eventually occur due to the interference of the characteristics of the puncture material. puncture. After doping the material, dilutions were performed up to the sensitivity limit of the test, also analyzing the functional sensitivity, where ten replicates of the material were dosed, thus obtaining CV%, mean and Standard Deviation values. The same process was carried out and evaluated using the serum material. During the entire process, the materials received and analyzed were centrifuged and always kept in a refrigerated environment. Results The recovery% of the matrix effect study for cervical aspirate puncture showed results within the expected range, ranging from 80% to 120%, as well as the results compared with serum/plasma referenced in the supplier's package insert. The functional sensitivity study for Thyroglobulin showed a CV% of 1.77%, being lower than that recommended by the package insert (2.2%) and for the Calcitonin analyte, the functional sensitivity study showed a CV% of 8.49%, being lower than recommended by the package leaflet (15.7%), in addition to having CV's lower than the 20% recommended by ANVISA. The results obtained with the matrix effect study for serum also showed values between 80% and 120%, both of which agreed. Conclusions The results showed excellent performance for material from fine needle aspiration for both Calcitonin and Thyroglobulin, being consistent with the serum data described by the suppliers' package inserts, thus making the reagent usable for the cervical aspirate puncture matrix.