Detection of microRNAs in dried serum blots.

We observed the preservation of microRNAs in unrefrigerated dried serum blots. Preservation was not adversely affected by drying or storing at 37, 45, or 60°C instead of room temperature, but it was harmed when blots were dried incompletely before storage. Preservation of microRNAs in serum was not diminished if, instead of being kept frozen at -80°C, it was stored as dried blots at room temperature for 5 months or at 37°C for 4 weeks. Thus, dried blots can be a convenient and safer way to save, transport, and store serum for microRNA assays.