Urine protein, the simplest test, can only be qualitative
Urine microalbumin, still simple, but can be quantitative
Urine albumin-to-creatinine ratio (UACR), combines microalbumin with creatinine correction, more accurate
The concentration of creatinine in urine is inversely proportional to urine volume. UACR uses the concentration of microalbumin divided by creatinine concentration to reduce the influence of urine volume on albumin results in random urine samples.
24-hour urine protein, other tests can be conveniently done with a small urine cup at one time, while 24-hour urine protein requires collecting the entire volume over a whole day, which is more cumbersome, so it is mainly done during hospitalization and is the gold standard for proteinuria.