A fluid assay system comprises a swab having an absorbent portion for receiving and retaining a fluid sample. The system also comprises an electrode module having at least one electrode, arranged so that it can be selectively placed over the absorbent portion of the swab in order to contact the electrode with the fluid sample. The system further comprises a reader module configured to process signals from the electrode module, with the electrode and reading modules arranged such that they can be coupled together for communication of the signals from the electrode module to the reader module.
