Fingernail Tests May Offer Cheap, Simple Way to Diagnose Diabetes

From 2015 AACC: Fingernail clippings could replace blood draws for diabetes tests, and a new biomarker could speed up tests for gestational diabetes.

A simple test of fingernail clippings could replace a blood draw as a way to diagnose and monitor type 2 diabetes mellitus (T2DM), with huge implications for tracking the disease the developing world.

Research on this method by a team of Belgian researchers was reported today at the 2015 American Association for Clinical Chemistry (AACC) Annual Meeting and Clinical Lab Expo in Atlanta.

The team, led by Joris R. Delanghe, MD, PhD, of the Department of Global Chemistry, Microbiology and Immunology at Ghent University, collected nail clippings from 25 people with T2DM and 25 without the disease. The clippings were ground into a powder and tested with an inexpensive instrument called a spectrometer to measure how much the protein in the nails had bonded with sugar molecules, a process known as glycation.

“We found a striking difference in the measurements between the control group and the patients with diabetes,” Delanghe said.

In an interview with The American Journal of Managed Care, he said replacing the standard blood test to measure glycated hemoglobin (A1C) is a huge advantage. In many cultures, he said, “taking blood is something that cannot be tolerated.”

As a practical matter, blood draws present safety, refrigeration, and storage problems for public health workers. Fingernail clippings, by contrast, are stable and can be stored for weeks at high temperatures. “All the equipment you need to analyze them can be stored in a car,” he said.

The concept of using fingernail clippings instead of the standard blood test grew out of discussions with graduate students, who advised that cultural barriers to drawing blood to diagnose T2DM had to be overcome. “It’s a nice example of how and exchange of ideas with people from various countries can lead to a new approach for diagnosing diabetes,” Delanghe said.

He is not seeking a patent on the idea, because he hopes it can be useful to public health officials in places like India and Southeast Asia where T2DM incidence is on the rise. This way, Delanghe said, “It will be available for everyone.”

A Faster Test for Gestational Diabetes

Sridevi Devaraj, PhD, director of clinical chemistry at Texas Children’s Hospital and a professor at Baylor College of Medicine, Houston, presented results at AACC today that could become a faster, earlier test for gestational diabetes. This serious condition puts pregnant women at risk of preeclampsia, which is characterized by high blood pressure and excess protein in the urine. Gestational diabetes can lead to difficult deliveries, which can be life-threatening.

The standard biomarker, A1C, has limited usefulness during pregnancy, but the current glucose tolerance test for pregnant women takes 3 hours and requires fasting—a process that Devaraj said is quite time-consuming and unpleasant. In addition, gestational diabetes cannot be diagnosed until 3 months into pregnancy

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Devaraj and her team collected blood samples from 124 pregnant women and examined 3 different blood proteins. They found that the levels of 1 protein, called 1,5-Anhydroglucitol or 1,5-AG, were significantly different from women already diagnosed with gestational diabetes. In addition, researchers were able to establish a cut-off level at which the 1,5-AG indicated which women had gestational diabetes.

She noted in an interview that her results are retrospective and must now be confirmed in a larger, prospective study. But Devaraj is hopeful that she is in the early stages of developing a better test that will spot gestational diabetes earlier in pregnancy, with better outcomes for mother and baby.

“The good thing with pregnant women is that they will come in for their checkups,” she said. “If the lab is there, they will do it.”