Abstract: A point of care testing assay system for determining the presence and/or amount of an analyte of interest in a sample, and methods for using such assay system, are disclosed. The system comprises a microfiuidic means capable of performing testing with low sample volume in a sample matrix, and having high sensitivity and substantially a 5-log wide dynamic range and capable of performing an assay in approximately fifteen minutes, and in which the microfiuidic means comprises a microfiuidic testing cartridge with associated electronics, a precision pipettor, a high sensitivity detection module, a motion stage, and an on-board electronics display means that can be read by a user as an indication of the presence and/or amount of the analyte in the sample.