Laboratories-on-a-chip pack the punch of an overnight testing facility, but get results in minutes by virtue of nanoliter-size chambers that speed up chemical reactions. Of the dozens of kinds of micropumps that can be used to fill those chambers, only a few avoid contaminating the nanoliter-size samples. Recently the University of Utah showed a design that avoids contamination via the use of vacuum-driven, plastic layered membranes. The beauty of the University of Utah design is that a tester the size of a deck of cards could contain hundreds or thousands of independent chambers, each prefilled with the reagents for an array of tests. Then, all the chambers could be supplied with the sample to be tested simultaneously, using nothing more that a battery-powered air pump. A reader no bigger than a deck of cards would accept blank, credit-card-size test cards. Its chambers would be filled with a sample from the patient, and the results of the test would be read out in minutes. After testing, the disposable card would be thrown away. Currently, patients have to wait overnight for a traditional medical lab to do the evening's batch run.