Table 1.

Brief comparison of the most commonly used methods for urinary exosome isolation

	Method	Advantages		Disadvantages
		Proteomic analysis	Transcriptomic analysis	Proteomic analysis	Transcriptomic analysis
1	UltraCentrifugation	Commonly used approach; provides a good and relatively pure yield	Usually no interference or contamination observed in RNA profiling after isolation procedures	Time consuming and costly; High content of Total soluble proteins from renal dysfunction patients can interfere with exosomal protein biomarker isolation; may require extra steps such as addition of reducing agents, SEC, sucrose gradient and DNAase treatment	Higher time consumption and expensive
2	Ultracentrifugation + Sucrose cushion	Can be used to remove interference from non exosomal proteins in the case of renal dysfunction patients	Particularly good yields for miRNA analysis	Time consuming, costly; Due to the density specific nature of the method, it may be disadvantageous for exosomes obtained from different pathways with unknown densities, as they would be hard to characterize	Time consuming and expensive
3	Ultrafiltration	Good total protein yield; faster and simpler procedure	Yield comparable to Ultracentrifugation	Urinary exosomes with Aquaporins and TSG101 require extra steps for isolation; Higher total protein content but very low exosomal protein purity; may not suitable for renal dysfunction patient samples	Comparably lower RNA purity
4	Polymer based Precipitation (Standard ExoQuick™)	Faster, simpler, relatively inexpensive	Faster, simpler, relatively inexpensive	Low purity and yield	Low purity and yield
6	Polymer based Precipitation (ExoQuick™ + Ultracentrifugation + DTT)	Good yield	Best yield and purity among all other methods	Purity can be improved with additional steps such as SEC	N/A