Hyperaldosteronism tests?

I've seen that ultrasound is used to test for hyperaldosteronism, is there also a blood test?  Is it a standard blood test that can be done in-house at my vet's?  My cat has CKD.

Hello and yes - there are a few ways in which blood tests can help with this diagnosis.  Most cats with hyperaldosteronism present with low Potassium levels or abnormally high blood pressure, so checking for either of these could provide a clue - but they are not necessarily diagnostic, because Potassium levels can be high for other reasons and are not high in every hyperaldosterone case - and the same can be said of blood pressure.  Merek's veterinary manual cites plasma renin activity, together with the Aldosterone : Renin ratio, as the gold standard test.  However, one would have to speak to laboratories about the availability of testing.

Usually, if vets feel that a blood or ultrasound test is necessary, they will be happy to explain the reasons for this - and if they don't feel that a test is necessary, I would expect the same.   As a next step, we would strongly advise speaking to them.