Catecholamines

[Ernie]

Hi,

My doctor ordered a 24-hour urine catecholamine and metanephrine test. What is this test used for? What can they learn more than with the blood catecholamine test?

I already know that I have too much blood adrenaline and for this test I have to stop my meds for 3 days. I don't know if it's worth my getting sick.

Any advice?

Ernie

[RunnerGirl]

Ernie:

I think we've corresponded about these tests before - so please forgive me if I'm repeating myself. :-)

As far as I know, the 24-hour urine catecholamine and metanephrine test is used almost exclusively to rule out pheochromocytoma. I've not heard it being used for any other purpose. The 24-hour urine cat and met test USED to be considered the 'gold standard' for ruling pheo in or out, but now the plasma free metanepherine test (developed by NIH) is the new standard. Urine testing has been known to produce both false negatives (if one has a tumor that only secretes episodically) and false positives (various meds and certain foods and beverages can cause falsely elevated cats). With the PFM test, the accuracy is MUCH greater - up to 99% accurate, according to some literature. So, if you get a negative PFM test, you can probably rest assured you do not have pheo.

If I remember correctly, you've already had pheo ruled out, yes? If not, it's probably a good idea to have the urine test, but also ask about the PFM test, too.

Good luck,

RG

[Ernie]

Thanks Runnergirl,

I can't remember if you are repeating yourself but I appreciate that you answered me. I don't know if pheo was ruled out because if ever I did this test it was at Vanderbilt and they never gave me any result of some sort on anything. So, to be on the safe side I will do the test. I thought that if they measured the catecholamines in the blood it would give the same answer as in the urine. Wow, it's very complicated to get tested.

Ernie

[morgan617]

I had the 24 hour test to rule out pheo, but it was normal. It seems the tests have to be far more specific to come up abnormal, such as the ones they do at the centers. I get very frustrated because all my tests always come back normal, or borderline, but have figured out it's because the tests are not specific for autonomic problems and therefore not done in a way that would show abnormalities. If you haven't been tested for pheo, it's a good test, but that's usually the first thing they look for. If you've had an abdominal mri or mra, then you shouldn't need it. But you should discuss with your doctor whether he's got any results of these before you decide. I have spent thousands out of pocket for things that didn't help one bit, and sure don't help my case with ssdi if they are all normal. And I hate to say this because of how it sounds, but the more tests they do that are normal the more I tend to think I'm a nutball. I don't want the tests to be abnormal, but if they are, I could at least feel normal!!!! morgan

[Ernie]

Hi Morgan,

I read somewhere this week that the new tendency for doctors is to write normal when we are abnormal because then they don't have to order more tests. I had an abnormal EMG a few months ago and I heard the neurologist tell the resident that even if had an abnormal test he was writting normal because it was not enough abnormal. Makes me wonder how reliable are the diagnosis. Also, the more I learn about doctors and their habits the more I realise that we have to be able to interpret the result and see if there is a problem with our body. This freaks me out!

Ernie