Abstract: Methods, materials, apparatus and systems are described for performing capillary flow assay. In one aspect, a system includes a sample collection unit to collect a sample liquid and a sample testing and storing unit to interface with the sample collection unit to test and store the collected sample liquid. The sample testing and storing unit includes a sample inlet shaped to receive the collected sample from the sample collection unit, and a sample well positioned below the sample inlet to retain at least a portion of the sample liquid. The sample testing and storing unit includes a sample housing unit to store a remainder of the sample liquid not retained in the sample well, and an analyte testing unit housing shaped to receive an analyte detecting unit to test a presence of a target analyte in the sample liquid.