Salad spinner brings blood test revolution

A salad spinner could revolutionise blood tests in the developing world as, after a few minor modifications, it has been converted into a centrifuge.

Lauren Theis and Lila Kerr from Rice University will test their pump-spun separator – named Sally Centrifuge after the Sallyport landmark on campus – abroad this summer as part of health initiative Beyond Traditional Borders.

The device – which is operated by a push-pump – spins tubes at up to 950 rpm and can spin 30 capillary tubes each containing 15 microlitres of blood at a time. It separates red blood cells and blood plasma after spinning for just 10 minutes. The hematocrit – the ratio of red blood cells to the total volume – can tell clinicians if a patient is anaemic, which can help in diagnosing malnutrition, TB, HIV/AIDS and malaria.

 “We were essentially told we need to find a way to diagnose anaemia without power, without it being very costly and with a portable device,” said Theis, a political science major. The device uses no electricity – just a bit of muscle, she said, adding that the centrifuge is both robust and durable.

Theis will take a device to Swaziland in June, while Kerr will visit Ecuador in late May. A third team will take one to Malawi in June. “We’re so excited, we’ve had this in the laboratory for a whole semester now,” said Kerr, a sociology major, “We’re just really eager to get it out into the field and see how it can be used and how it can potentially help people.”

The centrifuge is assembled using plastic lids, cut-up combs, yogurt containers and hot glue guns, and costs around $30 including the spinner.

“The students really did an amazing job of taking very simple, low-cost materials and creating a device their research shows correlates nicely with hematocrit levels in the blood,” said Maria Oden, the duo’s co-adviser, “Many of the patients seen in developing world clinics are anaemic, and it’s a sever healthy problem. Being able to diagnose it with no power with a device that’s extremely lightweight is very valuable.

Theis and Kerr will continue work on the device after their summer expeditions.