title: Evaluation of the BRAHMS Kryptor(®) thyroglobulin minirecovery test in patients with differentiated thyroid carcinoma.
abstract: BACKGROUND
  The present study was undertaken to evaluate a new sensitive thyroglobulin (Tg) mini-recovery test (Tg-mrec) for the detection of potential interferences in sera from patients with differentiated thyroid carcinoma (DTC) and low Tg levels.
  
  
  METHODS
  167 DTC patients with serum Tg <2 μg/L were enrolled. Both TgAb and Tg-mrec measurements were performed on the automated Kryptor(®) platform. Serum pretreatment in proprietory blocking tubes was perfomed to screen for heterophile antibody interferences. The concordance rates between tests were evaluated.
  
  
  RESULTS
  One case of over-recovery occurred in a patient with discordant Tg results in different immunoassays. The prevalences of a positive TgAb test and a reduced recovery rate were 15%-12%, respectively. Serum TgAb and Tg-mrec tests were both positive in 16 patients, both negative in 138 patients and discordant in 13 patients, respectively. The concordance rate between the Tg-mrec test and the TgAb assay was 92% (Cohens' kappa 0.894; 95% confidence interval: 0.82-0.93, p<0.001). In all, among seven clinically relevant interferences, three were found by TgAb, five by Tg-mrec and six by using both tests.
  
  
  CONCLUSIONS
  The automated Kryptor(®) Tg-mrec test has a complimentary value to TgAb immunoassay testing in the detection of potential interferences in Tg measurements in patients with DTC and low Tg values (i.e., <2 μg/L). Tg-mrec may detect interferences from TgAb not measured directly by an individual TgAb assay or from other interfering substances, such as heterophile antibodies.
authors.affiliation: Nuclear Medicine and Thyroid Centre, Oncology Institute of Southern Switzerland, Via Ospedale 12, CH-6500 Bellinzona, Switzerland. luca.giovanella@eoc.ch
authors.forename: Luca
authors.initials: L
authors.lastname: Giovanella
authors.forename: Mauro
authors.initials: M
authors.lastname: Imperiali
authors.forename: Frederik A
authors.initials: FA
authors.lastname: Verburg
authors.forename: Luca
authors.initials: L
authors.lastname: Ceriani
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood / Q000276:immunology; D002454:Cell Differentiation / Q000502:physiology; D005260:Female; D006801:Humans; D007118:Immunoassay; D008297:Male; D008875:Middle Aged; D013954:Thyroglobulin / Q000097:blood* / Q000276:immunology; D013964:Thyroid Neoplasms / Q000097:blood* / Q000276:immunology / Q000473:pathology*; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D013954:Thyroglobulin