Test module with low-volume reagent reservoir

A test module for biochemical processing and analysis, the test module comprising:

• an outer casing dimensioned for hand-held portability, the outer casing having a receptacle for receiving biochemical liquid;
• and,
• a reagent reservoir having a volume less than 1 μl and containing a reagent for addition to the biochemical liquid for use in chemical analysis of the biochemical liquid;
• wherein,
• the reagent reservoir has an outlet a surface tension valve, surface tension valve having a meniscus anchor for arresting flow out of the reagent reservoir by pinning a reagent meniscus at the meniscus anchor, the meniscus anchor being configured to position the reagent meniscus to contact the biochemical liquid added to the receptacle such that contact between the biochemical liquid and the reagent meniscus reconfigures the reagent meniscus to unpin the reagent meniscus from the meniscus anchor to allow the reagent to flow from the outlet.