[Comparison of three chemiluminescent methods with a radioimmunoassay for thyroglobulin measurement in the follow-up of differentiated thyroid cancer]. / Comparaison de trois methodes chimioluminescentes avec une methode radioimmunologique de dosage de la thyroglobuline dans le suivi des cancers differencies de la thyroide.

ABSTRACT

INTRODUCTION: Serum thyroglobulin measurements play an integral role in clinical evaluation of patients with thyroid cancer. Serum thyroglobulin is a highly specific and sensitive tumor marker for detecting persistent or recurrent thyroid cancer but also for monitoring clinical status. Actually, chemiluminescent methods gain ground on the radioimmunological methods because they offer the practical advantage of a shorter incubation time, a wider range of measured values and a reagent marked antibody more stable, less fragile than those used on radioimmunoassay. The aim of this study was to compare, by correlation study, three chemiluminescent methods to the reference radioimmunological method usually used in laboratories. MATERIALS AND METHODS: Thyroglobulin was measured in 203 patients by the 3 following analyzers Nichols Advantage (Nichols Institute Diagnostics, CA, USA), Immulite 2000 ( DPC Roche, Siemens, Los Angeles, USA) and Elecsys 2010 (Roche Diagnostics, Manheim, Germany); and by manual method (SELco Tg (Medipan Diagnostica, Berlin, Germany). Correlation analysis with OriginLab software version 7.0 was performed in order to compare thyroglobulin distribution values measured by the different methods. RESULTS: Correlation coefficients obtained were for Medipan/ Immulite 2000 0.95 (n = 80); for Medipan/Elecsys 0.97 (n = 31); for Medipan/Advantage r = 0.96 (n = 73). CONCLUSIONS: Chemioluminescent technics we studied could be validly used in patients without anti-thyroglobulin antibody. The correlation coefficients we obtained allow us to select one of these automated methods after their performance was studied.