Sunday, April 19, 2015

Testing for Cushing's, 24 hour UFCs

24 hour urinary free cortisol (UFC) is considered a gold standard by most doctors. 

Basically, you are given a urine collection jug, void at a specific time in the morning (8am is the standard given, but whatever time you first wake in the morning and go to the bathroom works, you just have to write down the time and make sure you collect the same time the following morning).  This first urine of the day you flush down the toilet, but that time is the official start of your test.  You then carefully collect every drop of urine the rest of that 24 hour period, usually with a "hat" you get from the lab, pour it into the collection jug, and unless it has an acid preservative tablet (most labs don't use those for this test these days) you have to keep the jug refrigerated during and after the test.  When you get up the following morning (at the end of your 24hr testing period) and pee in your hat for the last time at the same time you peed the following morning, you add this sample to your jug and the collection sample is now complete. 

You seal the lid, measure the volume on the side, write that volume on the jug along with whatever other information it requires --generally at least you name, often collection start and stop times and dates, maybe your ordering doctor's name, the test, etc-- and this information might also need to be added to the test requisition paper as well.  DO NOT forget to fill these out completely, and I advise you now to keep a log yourself of each test you do and include in this log the day, the test type, the total VOLUME of the sample collected, and the lab you submit it to if you are using different labs for different test types (I had to due to local restrictions).  It is VERY common for labs to order these wrong, to forget to write down total sample volume (and thus not calculate results), etc, etc.  It will always be aggravating, but being prepared in this way will at least mean that some of that effort can still be useful.  I've had friends take pictures of their labels with their cell to keep track.  I personally write the information down along with my daily symptom/sign/weight tracking that I am already doing so everything is in one place.

The biggest downfall of this test seems to be that it is totaling your cortisol output over a 24 hour period.  So, if you have a flipped (backwards) diurnal rhythm and your cortisol is high at night but low during the day, your average can still show up normal or just slightly elevated, even though you may quite ill.  It takes an astute doctor with experience to figure this out and know how to test more effectively...not to mention, a doctor who trusts his patient's symptomology. 

The second reason this 24 hour total can be a downfall is that more and more we are recognizing cyclic and episodic disease states where they alternate between high cortisol and normal or low cortisol states over periods of days, weeks, months, and possibly even years.  I was a fairly predictable cyclic case (cyclic basically means more predictable, episodic means less-so) and had roughly 2 weeks of highs and 2 weeks of lows.  If I were to collect my 24 hr UFC's in a low cycle, it would not show I was ill.  In fact, this is EXACTLY what I did with my first round of testing, because I didn't know better.  I had one or two marginal high tests (above the normal range, but not sufficient evidence) and the rest were normal.  Once I learned how to track my symptoms and could better gauge when to test, I moved on to a diagnosis.

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