How much water should I drink before collection?

Drink your normal, everyday amount of water before collection. Do not deliberately force fluids or restrict fluids in the hours before collecting. Very dilute urine (from excessive water intake) and very concentrated urine (from dehydration) are both handled by the Yenos HL normalization — because miRNA is expressed as a ratio of cancer marker to total RNA, moderate concentration differences are normalized out. However, extremely dilute urine (specific gravity below 1.003) may have very low total RNA content, potentially falling below the minimum threshold for valid HL normalization. Drinking normally throughout the day and collecting 2–4 hours after your last urination is the best approach.