You should be able to find commercial RIA test kits for mice to measure sex hormones in mice.

Dear Verena,

You can determine sex hormone (e.g Tes & E2) in Mice plasma samples using different methods.

Immunoassays such as RIA, EIA, CIA, FIA,...and also with Chromatography (e.g HPLC), or Mass Techniques such as GC-Mass and LC-Mass.

But as Ahmet and Nagaraj mentioned, immunoassay such as ELISA & RIA are common methods, Rapid and inexpensive methods.

But you can use Mouse Tes RIA / Mouse E2 RIA / Mouse Tes ELISA / Mouse E2 ELISA  which have price around USD700

As Mouse Tes concentration is around between 0.5-1.9 ng/ml  and human Tes ELISA or RIA kits have sensitivity around 0.02 ng/ml, and Tes has the same structure in human and Mice plasma samples,

So you can use non expensive human Tes or E2 ELISA assay kits for Mice samples too.

Of course you know matrix effect and it may change absolute accuracy of the hormone amount of Mouse Tes with Human ELISA kit.

But if your study is a comparative study such as Case/Control or Before /After study, you can use, human Tes ELISA kit or Human E2 ELISA kit with price around USD 100 instead of Mouse related ELISA kits with price around USD 700.

Best

Mehdi

ELISA or radioimmunoassay of blood serum samples is the way to go.  Essentially you clot the blood (~hour), spin down, collect the serum supernatant and then freeze the serum at -80C until your ready to measure with ELISA or RIA kit.  If you don't want to do it yourself or don't have the set up to do RIA or ELISA yourself, you can ship your serum sample to a core facility that will do them for you.  The University of Virginia has a a core facility to do hormone measurements of serum samples.

I second Paul Bonthuis's answer. We have very good experience with shipping samples to the University of Virginia core facility: http://www.medicine.virginia.edu/research/institutes-and-programs/crr/lab-facilities/ligand-page

EIA, CIA, FIA, RIA or mass spectrometry are all acceptable. If sensitivity is an issue the CIA or FIA may be better.