A system for determining the presence of cell-free non-coding RNA (cfNCR) biomarkers in interstitial fluid includes a microfluidic device for non-invasively and passively accessing interstitial fluid from a patient. The microfluidic device is formed of a substrate containing multiple vertical micro channels therethrough, wherein at a first end of each of the multiple vertical micro channels a microheater is formed for controllably ablating a portion of dry dead skin cells to access the interstitial fluid； and wherein at a second end of each of the multiple vertical micro channels is a horizontal micro channel for receiving accessed interstitial fluid from a vertical micro channel and guiding the accessed interstitial fluid to a common collection port.
