TRAV-005 (Needles) 62/795,857

A method of rapid functional analysis of cells is provided. A body fluid sample is introduced into a reservoir of a measurement instrument. A living cell is loaded directly from the body fluid sample into a channel of the measurement instrument in the absence of long-term cell culturing, cell pas-saging, and application of long-term drug pressure to cells. A functional biomarker of the living cells is measured while the living cell flows through the channel. The functional biomarker measured may be mass accumulation rate (MAR) or mass change. The measurement instrument may be a suspended microchannel resonator (SMR).