Some unfortunate individuals have to give blood for tests very, very often. A powerful, small surface area vacuum could draw blood from unpierced skin with less pain and from less sensitive, faster healing areas of the body. Also would be effective with small children. Would create an unsightly bruise, but some needle-blood drawing does that anyways. Could be effective in letting over-drawn areas of the body heal, rather than being pierced and re-pierced by a needle.
-- naveline, Jul 15 2000

painless blood sugar test http://webmd.lycos..../article/1728.55291
Blood test using ultrasound [egnor, Jul 15 2000, last modified Oct 04 2004]

Plug & Play Body Parts http://www.halfbake...Play_20Body_20Parts
Just get yourself outfitted with a "blood test interface". [egnor, Jul 15 2000, last modified Oct 04 2004]

Instant hickey. Leeches <real ones> work by anesthetizing the skin then cutting it with their tongue. It would hurt like hell to have it suck hard enough to get blood out...
-- StarChaser, Jul 15 2000


As StarChaser alludes, vacuum alone is not sufficient to draw blood through the skin. According to the link I've added, though, ultrasound can make the skin permeable (how does that work?), allowing a vacuum to draw fluid.

Unfortunately, I suspect that actual cells are too big to fit through, so this is limited to things like glucose tests that can be performed on serum alone.
-- egnor, Jul 15 2000


Why not just use real leeches? They are superbly adapted for the task of imperceptibly drawing blood (plus, presumably, cells and other items of interest). A bit of genetic engineering could inhibit the leeches normal digestive processes so as not to damage the blood so drawn.

Further engineering could provide special purpose leeches which would test the blood for specific conditions, and give an indication of the result by changing colour.
-- Mickey the Fish, Jul 16 2000


Because you'd keep losing patients from having them grossed out of existence...

Kind of like using maggots to clean infected wounds. <Yes, they do actually do this.>
-- StarChaser, Jul 16 2000


How about specially-bred tapeworms as a dietary/weight-loss aid?
-- supercat, Jul 19 2000


'You want me to put that 20 foot worm WHERE?'
-- StarChaser, Jul 20 2000



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