While performing ELISA or RIA, you must run a known concentration along with your tested one which will gives you an Idea about the what concentration you have to be compared with. In ELISA, we can perform an experiments with serial dilutions of your interested drugs/ chemicals against the antibodies. Here in this case Oxytocin can be taken with serial dilution concentration to do its standardization curve.

While performing ELISA or RIA, you must run a known concentration along with your tested one which will gives you an Idea about the what concentration you have to be compared with. In ELISA, we can perform an experiments with serial dilutions of your interested drugs/ chemicals against the antibodies. Here in this case Oxytocin can be taken with serial dilution concentration to do its standardization curve.

Hello

i agree with Sharad Ramchandra Kamble  , See these links 

Good Luck 

http://link.springer.com/article/10.1007/s00580-015-2148-2

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2836837/

https://www.karger.com/Article/Pdf/327398

thanks!