A sample metering device for a liquid sample comprises at least one capillary passage with an inlet and an outlet; a side passage extending from the capillary passage part way along the length thereof and leading to an outlet; a fluid application region for receiving a liquid sample to be tested, for entry to the capillary passage via the inlet; first sealing means operable releasably to seal the outlet of the capillary passage; and second sealing means operable releasably to seal the outlet of the side passage.
