The PTH ELISA is an enzyme immunoassay intended for the quantitative determination of parathyroid hormone in serum. It detects total PTH (intact PTH, iPTH).

For research use only. Not for use in diagnostic procedures.

For Laboratory Professional Use Only.

Developed by Immundiagnostik AG.

Test Principle of the PTH ELISA

The PTH ELISA utilizes the two-site sandwich technique with two selected polyclonal goat antibodies that bind to human PTH. Standards, controls, and samples assayed for human PTH are added to
the wells of microplate coated with streptavidin. Then, the biotinylated antibody (AB), directed against the middle and C-terminal PTH sequence 39-84, and the peroxidase-labeled antibody (CONJ), detecting the N-terminal amino acids 1-34, are added to the wells.

During the first incubation step, the antibodies bind the PTH in the samples. Simultaneously, the biotinylated antibody binds to the streptavidin on the plate. The following complex is formed at the bottom of the microtitre plate: streptavidin – biotinylated antibody – human PTH – peroxidase-labeled conjugate.

After a washing step, tetramethylbenzidine (TMB) is added as a substrate for the peroxidase. Finally, an acidic stop solution is used to terminate the reaction. The color changes from blue to yellow. The intensity of the yellow color is directly proportional to the PTH concentration of the sample.

A dose-response curve of the absorbance unit (optical density, OD) vs. concentration is generated using the values obtained from the standards on the plate. PTH present in the samples is determined directly from this curve.