Patent ID: 8092394

Claim:
An allergy-testing device, the device having a housing with a bore and a lancet slidably fitting in the bore, the lancet being a penetrating component and being movable between a puncture position, in which a sharpened tip of the lancet is exposed from a forward end of the bore for a puncture operation, and a retracted position, in which the lancet is rearwardly displaced along the bore to a safe position to protect users from needle-stick injuries, the device having seal means in sliding engagement with a sealing surface, one of the seal means and the sealing surface being fixedly movable with the lancet during forward and rearward displacement of the lancet, wherein in the retracted position a liquid-containing space is defined in the bore forwardly of the lancet tip, an aqueous liquid contained in the liquid-containing space comprising an aqueous solution of allergen or a suspension of allergen particles in a carrier liquid, the liquid-containing space having a cross-sectional diameter of 3 mm or less to allow aqueous liquid to fully bridge across the diameter of the forward end of the bore and wet the full circumference of the forward end of the bore and be aspirated into the liquid-containing space, and be retained in the liquid-containing space by surface tension forces and by the seal means, wherein the seal means is operable substantially to prevent flow of the aqueous liquid from the liquid-containing space past the seal means on forwards, and rearwards displacement of the lancet and to oppose dripping of the aqueous liquid from the forward end of the bore under the influence of gravity so that: (i) displacement of the lancet from the puncture position to the retracted position provides suction for drawing aqueous liquid into and along the liquid-containing space from the forward end of the bore, and (ii) displacement of the lancet from the retracted position to the puncture position provides pressure for expelling aqueous liquid from the liquid-containing space via the forward end of the bore; wherein the device further includes a spacer member located forwardly of the forward end of the bore, the spacer member being for contact with the skin of a subject, the spacer member including a vent which vents the spacer member and the forward end of the bore when the sealing means is in sealing engagement with the sealing surface and the spacer member is pressed against the skin of the subject; wherein the seal means is formed by the outer surface of the lancet, the sealing surface being an internal surface of the bore.