Abstract: Test apparatus includes a sample receiver operable to receive a sample to be tested, a sample manipulator operable to manipulate a received sample, a reagent receiver operable to add to the received sample a reagent, and a result indicator operable to indicate whether the received sample contains a substance reactable with the reagent. Two or more of the elements of the apparatus are provided on a common substrate. The apparatus is designed to test small size samples, for example a drop of blood or less, typically a sample of the order of 5 ?l. It includes a manipulator able to manipulate a small size sample and an electrical field generator operable to move a sample under test through the apparatus.