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Published on: March 23, 2018
A new chemiluminescence immunoassay for triiodothyronine and thyroxine: evaluation using quality control sera assayed
G C Zucchelli1, A Pilo, S Masini
1Istituto di Fisiologia Clinica, Consiglio Nazionale delle Ricerche, Pisa, Italy.
Insights
The LIA-mat system demonstrates reliable performance for measuring triiodothyronine (T3) and thyroxine (T4) levels. This chemiluminescence immunoassay shows excellent agreement with established methods in interlaboratory quality control and patient serum analysis.
Area of Science:
- Clinical Chemistry
- Immunoassay Technology
- Endocrinology
Background:
- Thyroid hormones, triiodothyronine (T3) and thyroxine (T4), are crucial for metabolic regulation.
- Accurate quantification of T3 and T4 is essential for diagnosing and monitoring thyroid disorders.
- Existing immunoassay methods, including radioimmunoassays and enzyme immunoassays, have varying performance characteristics.
Purpose of the Study:
- To evaluate a newly developed chemiluminescence immunoassay system (LIA-mat) for T3 and T4.
- To compare the LIA-mat system's performance against established radioimmunoassays and a chemiluminescence enhanced enzyme immunoassay (Amerlite).
- To assess the LIA-mat system's accuracy and precision using interlaboratory quality control materials and patient sera.
Main Methods:
- The LIA-mat system utilizes competitive immunoassays with monoclonal antibodies and T3/T4-aminobutylethylisoluminol (ABEI) conjugates.
- Assays were performed on control materials from a national interlaboratory quality control scheme and patient serum samples.
- Performance was evaluated by comparing LIA-mat results with consensus means from participating laboratories using regression analysis.
Main Results:
- The LIA-mat T3 assay demonstrated a working range of 1.4–12.3 nmol/l with between-assay precision of 8.1–19.3% CV.
- Regression analysis for T3 showed strong agreement (y = -0.14 + 1.05x, r = 0.95) with interlaboratory consensus means.
- The LIA-mat T4 assay had a working range of 33–515 nmol/l and between-assay precision of 5.4–9.2% CV, with excellent agreement (y = 3.79 + 1.02x, r = 0.98).
Conclusions:
- The LIA-mat system provides accurate and precise measurements for both triiodothyronine and thyroxine.
- The evaluated chemiluminescence immunoassay system shows excellent concordance with established methods.
- LIA-mat is a viable alternative for routine T3 and T4 determination in clinical laboratories.
Abstract:
A recently developed chemiluminescence immunoassay system (LIA-mat) for triiodothyronine and thyroxine, set up by Byk-Sangtec Diagnostica (Dietzenbach, Germany), has been evaluated and compared with radioimmunoassays and with a chemiluminescence enhanced enzyme immunoassay (Amerlite), using control materials circulated in a national interlaboratory quality control, as well as patient sera. The LIA-mat assays are competitive methods which use coated monoclonal antibodies and triiodothyronine- or thyroxine-ABEI (aminobutylethylisoluminol) conjugate as tracers. The working range of LIA-mat T3 (computed from the within-assay precision profile) extended from 1.4 to 12.3 nmol/l; the between-assay precision was 8.1 - 19.3 CV%. Regression analysis of the LIA-mat T3 results (y) against the consensus means (x) of the participants in the national interlaboratory survey yielded: y = -0.14 + 1.05 x, r = 0.95. The working range of LIA-mat T4 extended from 33 to 515 nmol/l; the between-assay precision was 5.4 - 9.2 CV%. An excellent agreement was found between LIA-mat T4 results (y) and the consensus means (x) of the laboratories participating in the national interlaboratory survey (y = 3.79 + 1.02 x, r = 0.98).
