Blood Tests With Rainbows and No Needles

Few outings conjure up as much fear in a child as a visit to the dentist or the doctor. Drills, needles, bright lights, and sterile environments are no place for a kid's imagination. But what if rainbows came into play? A new microscope developed by a team in Israel can perform a blood test in real-time without any needles. And it uses a rainbow to do it.

The microscope operates by shining a light through the skin, revealing the blood vessels underneath and then creating a high-resolution image.  The breadbox-sized device creates an image by splitting a beam of light into different colors, from red to violet, just like a rainbow. As the blood cells flow underneath the microscope, they scatter the light. The scattered light is then processed by a computer, and physicians and researchers get a look inside our bodies without the need for invasive devices or dyes.

"We have invented a new optical microscope that can see individual blood cells as they flow inside our body," says Lior Golan, a graduate student in the biomedical engineering department at the Israel Institute of Technology and one of the authors of the paper.

The possibilities are astounding. Real-time results can allow physicians to spot problems before they get too severe. Even a few days waiting for results can be fatal when monitoring a teetering white blood cell count in an ill patient.

The researchers demonstrated the device by imaging the blood from a volunteer's lower lip. Due to the resolution and quality of the image they received, they were able to calculate the average diameter of red and white blood cells, as well as the percent volume of different cell types. All this with no blood lost.

There are still kinks to be worked out, however. The narrow field of view of the microscope makes it difficult to locate suitable capillary vessels to image. They attempted to add a wider green LED light, but the hemoglobin absorbed the green light and the vessels appeared dark.

As of now, other blood-imaging devices exist, but they are bulky and require harmful fluorescent dyes to be injected into the patient.

"Currently, the probe is a bench-top laboratory version about the size of a small shoebox," says Golan. "We hope to have a thumb-size prototype within the next year."

And hopefully, within the next few years, there will be a lot less crying babies and toddlers at the hospital.