PMID- 28720678
OWN - NLM
STAT- MEDLINE
DCOM- 20171013
LR  - 20191210
IS  - 1530-8561 (Electronic)
IS  - 0009-9147 (Linking)
VI  - 63
IP  - 10
DP  - 2017 Oct
TI  - Standardization of Free Thyroxine Measurements Allows the Adoption of a More 
      Uniform Reference Interval.
PG  - 1642-1652
LID - 10.1373/clinchem.2017.274407 [doi]
AB  - BACKGROUND: The IFCC Committee for Standardization of Thyroid Function Tests 
      intended to standardize free thyroxine (FT(4)) immunoassays. We developed a 
      Systeme International d'Unites traceable conventional reference measurement 
      procedure (RMP) based on equilibrium dialysis and mass spectrometry. We describe 
      here the latest studies intended to recalibrate against the RMP and supply a 
      proof of concept, which should allow continued standardization efforts. METHODS: 
      We used the RMP to target the standardization and reference interval (RI) panels, 
      which were also measured by 13 manufacturers. We validated the suitability of the 
      recalibrated results to meet specifications for bias (3.3%) and total error 
      (8.0%) determined from biological variation. However, because these 
      specifications were stringent, we expanded them to 10% and 13%, respectively. The 
      results for the RI panel were reported as if the assays were recalibrated. We 
      estimated all but 1 RI using parametric statistical procedures and hypothesized 
      that the RI determined by the RMP was suitable for use by the recalibrated 
      assays. RESULTS: Twelve of 13 recalibrated assays had a bias, meeting the 10% 
      specification with 95% confidence; for 7 assays, this applied even for the 3.3% 
      specification. Only 1 assay met the 13% total error specification. Recalibration 
      reduced the CV of the assay means for the standardization panel from 13% to 5%. 
      The proof-of-concept study confirmed our hypothesis regarding the RI but within 
      constraints. CONCLUSIONS: Recalibration to the RMP significantly reduced the 
      FT(4) immunoassays' bias, so that the RI determined by the RMP was suitable for 
      common use within a margin of 12.5%.
CI  - (c) 2017 American Association for Clinical Chemistry.
FAU - De Grande, Linde A C
AU  - De Grande LAC
AD  - Department of Pharmaceutical Analysis, Faculty of Pharmaceutical Sciences, Ghent 
      University, Ghent, Belgium.
FAU - Van Uytfanghe, Katleen
AU  - Van Uytfanghe K
AD  - Ref4U, Laboratory of Toxicology, Faculty of Pharmaceutical Sciences, Ghent 
      University, Ghent, Belgium.
FAU - Reynders, Dries
AU  - Reynders D
AD  - Department of Applied Mathematics, Computer Science and Statistics, Faculty of 
      Sciences, Ghent University, Ghent, Belgium.
FAU - Das, Barnali
AU  - Das B
AD  - Biochemistry and Immunology Laboratory, Kokilaben Dhirubhai Ambani Hospital and 
      Medical Research Institute, Mumbai, India.
FAU - Faix, James D
AU  - Faix JD
AD  - Clinical Chemistry and Immunology, Montefiore Medical Center, and Department of 
      Pathology, Albert Einstein School of Medicine, New York, NY.
FAU - MacKenzie, Finlay
AU  - MacKenzie F
AD  - Birmingham Quality/UK NEQAS, University Hospitals Birmingham NHS Foundation 
      Trust, Birmingham, UK.
FAU - Decallonne, Brigitte
AU  - Decallonne B
AD  - Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium.
FAU - Hishinuma, Akira
AU  - Hishinuma A
AD  - Department of Infection Control and Clinical Laboratory Medicine, Dokkyo Medical 
      University, Tochigi, Japan.
FAU - Lapauw, Bruno
AU  - Lapauw B
AD  - Department of Endocrinology, Ghent University Hospital, Ghent, Belgium.
FAU - Taelman, Paul
AU  - Taelman P
AD  - Laboratory of Endocrinology, Department of Laboratory Medicine, AZ 
      Maria-Middelares Sint-Jozef, Campus Maria-Middelares, Ghent, Belgium.
FAU - Van Crombrugge, Paul
AU  - Van Crombrugge P
AD  - Department of Endocrinology, OLV Ziekenhuis Aalst-Asse-Ninove, Aalst, Belgium.
FAU - Van den Bruel, Annick
AU  - Van den Bruel A
AD  - Department of Endocrinology, General Hospital Sint Jan, Bruges, Belgium.
FAU - Velkeniers, Brigitte
AU  - Velkeniers B
AD  - Department of Endocrinology, Universitair Ziekenhuis Brussel, Brussels, Belgium.
FAU - Williams, Paul
AU  - Williams P
AD  - Department of Endocrinology, Royal Prince Alfred Hospital, Camperdown, Australia.
FAU - Thienpont, Linda M
AU  - Thienpont LM
AD  - Department of Pharmaceutical Analysis, Faculty of Pharmaceutical Sciences, Ghent 
      University, Ghent, Belgium; linda.thienpont@ugent.be.
AD  - Thienpont & Stockl Wissenschaftliches Consulting GbR, Rennertshofen (OT 
      Bertoldsheim), Germany.
CN  - IFCC Committee for Standardization of Thyroid Function Tests (C-STFT)
LA  - eng
PT  - Journal Article
PT  - Validation Study
DEP - 20170718
PL  - England
TA  - Clin Chem
JT  - Clinical chemistry
JID - 9421549
RN  - Q51BO43MG4 (Thyroxine)
SB  - IM
MH  - Calibration
MH  - Chromatography, Liquid/methods/standards
MH  - Humans
MH  - Immunoassay/methods/standards
MH  - Limit of Detection
MH  - Reference Values
MH  - Tandem Mass Spectrometry/methods/standards
MH  - Thyroid Function Tests/*methods/*standards
MH  - Thyroxine/analysis/*blood
EDAT- 2017/07/20 06:00
MHDA- 2017/10/14 06:00
CRDT- 2017/07/20 06:00
PHST- 2017/03/30 00:00 [received]
PHST- 2017/06/13 00:00 [accepted]
PHST- 2017/07/20 06:00 [pubmed]
PHST- 2017/10/14 06:00 [medline]
PHST- 2017/07/20 06:00 [entrez]
AID - clinchem.2017.274407 [pii]
AID - 10.1373/clinchem.2017.274407 [doi]
PST - ppublish
SO  - Clin Chem. 2017 Oct;63(10):1642-1652. doi: 10.1373/clinchem.2017.274407. Epub 
      2017 Jul 18.