TSH CLIA kits - (Chemiluminescence Immuno Assay) description:

Chemiluminescence Immunoassay (CLIA) detection using Microplate luminometers provides a
sensitive, high throughput, and economical alternative to conventional colorimetric methodologies, such as Enzyme-linked immunosorbent assays (ELISA). ELISA employs a label enzyme and a colorimetric substrate to produce an amplified signal for antigen, haptens or antibody quantitation. This technique has been well established and considered as the of choice for a wide variety of applications in diagnostics, research, food testing, process quality assurance and quality control, and environmental testing. The most commonly used ELISA is based on colorimetric reactions of chromogenic substrates, (such as TMB) and label enzymes. Recently, a chemiluminescent immunoassay has been shown to be more sensitive than the conventional colorimetric method(s), and does not require long incubations or the addition of stopping reagents, as is the case in some colorimetric assays. Among various enzyme assays that employ lightemitting reactions, one of the most successful assays is the enhanced chemiluminescent immunoassay involving a horseradish peroxidase (HRP) labeled antibody or antigen and a mixture of chemiluminescent substrate, hydrogen peroxide, and enhancers. The CLIA Kits are designed to detect glow-based chemiluminescent reactions. The kits provide a broader dynamic assay range, superior low-end sensitivity, and a faster protocol than the conventional colorimetric methods. The series of the kits covers Thyroid panals, such as T3, T4, TSH, Hormone panels, such as hCG, LH, FSH, and other panals. They can be used to replace conventional colorimetric ELISA that have been widely used in many research and diagnostic applications. Furthermore, with the methodological advantages, Chemiluminescent immunoassay will play an important part in the Diagnostic and Research areas that ELISAs cannot do. The CLIA Kits have been validated on the MPL2 microplate luminometer from Berthold Detection System, Lus2 microplate luminometer from Anthos, Centro LB960 microplate luminometer from Berthold Technologies, and Platelumino From Stratec Biomedical Systems AG. We got acceptable results with all of those luminometers.

The determination of serum or plasma levels of thyroid stimulating hormone (TSH) is recognized as a
sensitive method in the diagnosis of primary and secondary hypothyroidism. TSH is secreted by the
anterior lobe of the pituitary gland and induces the production and release of thyroxine and
triiodothyronine from the thyroid gland. It is a glycoprotein with a molecular weight of approximately
28,000 daltons, consisting of two chemically different subunits, alpha and beta. Although the
concentration of TSH in the blood is extremely low, it is essential for the maintenance of normal thyroid
function. The release of TSH is regulated by a TSH-releasing hormone (TRH) produced by the hypothalamus. The levels of TSH and TRH are inversely related to the level of thyroid hormone. When there is a high level of thyroid hormone in the blood, less TRH is released by the hypothalamus, so
less TSH is secreted by the pituitary. The opposite action will occur when there is decreased thyroid
hormone in the blood. This process is known as a negative feedback mechanism and is responsible for
maintaining the proper blood levels of these hormones. TSH and the pituitary glycoproteins: luteinizing
hormonee (LH), follicle-stimulating hormone (FSH), and human chorionic gonadotropin (hCG), have
identical alpha chains. The beta chain is distinct but does contain identical amino acid sequences,
which can cause considerable cross-reactivity with some polyclonal TSH antisera. The use of a monoclonal antibody in this TSH EIA test eliminates this interference, which could result in falsely
elevated TSH values in either menopausal or pregnant females--a population whose evaluation of
thyroid status is clinically significant.

The TSH CLIA test utilizes a unique monoclonal antibody directed against a distinct antigenic determinant on the intact TSH molecule. Mouse monoclonal anti-TSH antibody is used for solid phase
(microtiter wells) immobilization and a goat anti-TSH antibody is in the antibody-enzyme (horseradish
peroxidase) conjugate solution. The test sample is allowed to react simultaneously with the two antibodies, resulting in the TSH molecules being sandwiched between the solid phase and enzymelinked
antibodies. After a 60 minutes incubation at room temperature, the wells are washed 5 times by
wash solution to remove unbound anti-TSH conjugate. A solution of chemiluminescent substrate is
then added and read relative light units (RLU) in a Luminometers. The intensity of the emitting light is
proportional to the amount of enzyme present and is directly related to the amount of TSH in the sample. By reference to a series of TSH standards assayed in the same way, the concentration of TSH
in the unknown sample is quantified.