Has someone determined in parallel cortisol on urine without additives and on urine collected on acid?
Hi,
Urine cortisol can be measured by EIA cortisol kit from Cayman (Item No. 500360). This EIA kit is dedicated for urine, plasma and feces samples. I use Caymans EIA kits since years with success.
Protocol is added in attachment
good luck,
Hanna
Hi Nicole, my EIA assay of cortisol is able to analyze in urine as a lot of commercial kits as those of Cayman chemicals. In fact urine is not a so complex medium as blood serum or saliva and normally does not contain lot of proteins that could interfere with antibodies. You have just to correct PH to obtain more physiological Ph for your antibodies and it is probable that you could assay without extraction. If required, use a simple Ethanolic precipitation (Pure iced 100% ethanol), followed by a vigorous mixing during 10 min and centrifugation. That could be sufficient and permit concentration of supernatant if required by a bad sensitivity of immunoassay.
Good luck
thank you for your reply and Hanna and Pierre. I should clarify my question. My problem is not to have a technique for assaying urinary cortisol. It is whether it can be performed on urine collected on acid. With a technique like the one sent by Hanna, performed directly on urine, the answer is no, you can not do it. But if there is first an extraction with dichloromethane for example, the response from a theoretical point of view is yes. But I never made the comparison and I would like to know if someone has already done it.
If you ask the question, why do the dosage on acidified urine? because urine is collected during 24 hours on acid for the determination of catecholamines and because cortisol is often determinated on this sample.
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