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How to Turn a Salad Spinner Into a Medical Centrifuge for $30

DiscoblogBy Eliza StricklandMay 5, 2010 10:24 PM


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The necessary parts: one salad spinner, some hair combs, a yogurt container, plastic lids, and a glue gun. The finished product: a manual, push-pump centrifuge that could be a lifesaver in developing world medical clinics. Its name: the Sally Centrifuge.

A team of college students invented this low-cost centrifuge, which can be built for about $30, as a project for a global health class at Rice University. The teacher challenged them to build an inexpensive, portable tool that could diagnose anemia without access to electricity, and the tinkerers got to work.

The students, Lila Kerr and Lauren Theis, found that spinning tiny tubes of blood in the device for 10 minutes was enough to separate the blood into heavier red blood cells and lighter plasma. Then they used a gauge to measure the hematocrit, the ratio of red blood cells to the total volume. That information tells a doctor whether a patient is anemic, which can in turn help to diagnose conditions like malnutrition, tuberculosis, HIV/AIDS, and malaria.

In a press release, Rice University listed some of the advantages of the Sally Centrifuge:

It requires no electricity - just a bit of muscle. "We've pumped it for 20 minutes with no problem," Theis said. "Ten minutes is a breeze."

It has proven to be fairly robust. "It's all plastic and pretty durable," Kerr said. "We haven't brought it overseas yet, of course, but we've trekked it back and forth across campus in our backpacks and grocery bags and it's held up fine."

This summer a team of students will fan out across the globe to test the device, with tryouts expected in medical clinics in Ecuador, Malawi, and Swaziland.

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Image: Jeff Fitlow/Rice University

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