An Immunochemiluminometric Assay for Serum Free Thyroxine

Abstract

An immunochemiluminometric assay has been developed for the measurement of free T4 concentrations in serum. The assay uses chemiluminescent acridinium ester labelled monoclonal antibodies which react with free T4 in the sample. A T4-rabbit immunoglobulin G conjugate competes for antibody binding sites, immune-complexes containing this being isolated using an anti-immunoglobulin G antibody coupled to paramagnetic particles. Associated chemiluminescence intensity is thus dependent on the free T4 concentration. The assay distinguishes patients with primary thyroid disease from euthyroid subjects and is unaffected by abnormal binding proteins which compromise the diagnostic accuracy of radiolabelled analogue immunoassays. the test yields results which accurately reflect the clinical thyroid status of euthyroid patients with a variety of acute and chronic non-thyroid illnesses. This is again in marked contrast to the aberrant results seen using certain radiolabelled analogue procedures.

Electrogenerated Chemiluminescence of Methyl-9-(p-formylphenyl) Acridinium Carboxylate Fluorosulfonate and Its Applications to Immunoassay

“…A lot of chemiluminescent immunoassay methods based on the acridinium ester have been reported (16)(17)(18)(19)(20). Kankare and co-workers (21) reported the use of chelating agents as an immunoassay label in ECL research.…”

Investigation of acridinium labelling for chemiluminescence detection of peptides separated by capillary electrophoresis

“…Acridinium esters have been used as chemiluminescent (CL) labels for immunoassays [1,2]. The CL reaction involves the oxidation of an acridinium ester by hydrogen peroxide in the presence of a base to produce N-methylacridone in the excited state, which upon relaxation emits a photon.…”

Quantitative determination of noncovalently bound acridinium in protein conjugates by liquid chromatography/electrospray ion trap mass spectrometry

“…1) have drawn considerable attention as chemiluminescent labeling reagents for use in immunoassays. They provide attractive features for use as signal generators such as superior detectability,13 well‐characterized structure, and low background 14–16. This has led to a rapid growth in the use of acridinium‐based chemiluminescence assay systems.…”