Lipiduria or lipuria is the presence of lipids in the urine. Lipiduria is most frequently observed in nephrotic syndrome where it is passed as lipoproteins along with other proteins. It has also been reported as a sign following fat embolism. When lipiduria occurs, epithelial cells or macrophages contain endogenous fats.

The medical term for having fats or lipids in your urine is lipiduria, and it’s one of the main causes of oily urine. This often happens when kidney diseases damage the kidney’s filtration barrier, which is there to keep larger molecules like fats out of your urine. When this barrier is damaged, fats can leak into your urine, making it look oily.