Table 2.

Comparison of methods of uEV particle normalization

Normalization Method	Notes
Urine flow (i.e., calculate excretion rate)	Requires timed urine collection
	Uncertainty over how uEV excretion is regulated; effects of urine flow rate, etc.
Creatinine concentration	Excretion influenced by muscle mass, acute changes in GFR, drugs affecting tubular transport
	[Creatinine] correlated with uEV particle number7
Osmolality	Affected by both water and osmolar load7
Uromodulin (THP)	Abundance correlates with uEV particle number11
	Wide intersubject variation in excretion
uEV marker proteins	CD9/CD63 only expressed in distal nephron segments7

THP, Tamm-Horsfall protein.