A "Uric Acid - Urine 24 Hrs" test measures the amount of uric acid excreted in your urine over a 24-hour period, primarily used to diagnose conditions like gout, where high uric acid levels can lead to crystal formation in joints, or to assess potential kidney stone formation related to uric acid buildup; it involves collecting all your urine for 24 hours and then sending it to a lab for analysis.