Abstract: A system for analyzing a biological fluid or the like includes a series flow loop that extends between an inlet valve array and an outlet valve array. The flow loop includes an analysis region to which a measuring system is connected in sensing relation and an accumulator chamber connected to the outlet of the analysis region. The inlet valve array is arranged to selectively and alternately connect a sample inlet port and an auxiliary fluid reservoir to the flow loop while the outlet valve array is arranged to selectively connect a controlled source of reduced pressure to the flow loop.