Dear you can use ELISA kit from Elabscience.

The commercial ELISA kits tested in the present experiment yielded different values of total corticosterone in the same serum samples from rats. The precision in determining the true value of the corticosterone level is low for these commercial ELISA kits. For comparisons of corticosterone levels between studies, it is essential to know which kit was used. Although exact levels of corticosterone are difficult or impossible to determine, these kits may be used to determine relative differences within studies. One should be aware of the fact that “total corticosterone” as some manufacturers state, may not actually represent the total amount of corticosterone.

There are a number of chemistry analyzer manufacturer that provide turbidimetric or nephelometric reagents for measuring IgG in serum.

Talk to the chemistry laboratory at your nearest hospital and they could probably help you. Siemens, Beckman, Roche and Abbott all have FDA approved (510(k)) reagents for measuring IgG and probably a number of other manufacturers. The assays give similar results according to external quality assurance programs so you would expect similar results regardless which manufacturer that you use.

Link to FDA approval of the Siemens reagent:

https://www.accessdata.fda.gov/cdrh_docs/reviews/K083445.pdf

Thank you for your suggestion. Maybe I should rephrase my question: I am looking for a manual assay (like ELISA) that can be used for determining Human total IgG in serum samples.

The problem with ELISA is that the serum koncentration of IgG is around 5-10 g/L and most ELISAs measure in the ug/L range. I hope you are very accurate when you do the dilutions.