How to measure output with Foley urometer/urimeter chamber?

Reposted from MICU/SICU forum:

I have a question about the collection chambers on the front of the Foley bag. There are 2 chambers. When you are reading the hourly output, and it is more than the 50 cc in the smaller chamber, it spills over into the larger chamber. Do you take the reading from the large chamber and add the 50 cc, or do you only take the measurement from the larger chamber? Any help would be appreciated!

[Daytonite, BSN, RN]

That will only work accurately if you empty the urine out of the large and small chamber at the end of every hour.

[ShortStackRN]

I'm not sure you can get an accurate reading from the chamber. You need to empy the urine into a graduator or some other container to be able to accurately measure.