Diseases like thyroid cancer, type-1 diabetes, and HIV, are extremely difficult to detect in the early stages. But that might be about to change.
Researchers from Stanford University have developed a new technique for testing that is 10,000 times more sensitive than the tests currently available. They published their work in the American Chemical Society’s journal Central Science.
When we’re sick—with a cold or flu, or something more serious like cancer—our bodies produce chemicals called antibodies that can be found in our blood or saliva. These antibodies are produced in response to antigens, which are chemicals our immune systems recognize as foreign and potentially harmful. Each antigen has its own unique antibody; if doctors find a specific antibody, they can pinpoint exactly what is making someone sick. The trouble is, early on in the course of an illness, our immune systems haven’t made enough antibodies to detect. Often, patients aren’t diagnosed until the disease has progressed and they’re showing symptoms.
Testing for antibodies is challenging because they’re protein, as opposed to genetic information, explained Peter Robinson, a graduate student at Stanford and co-author of the paper. Genetic information is easier to find, because scientists replicate tiny, unique snippets of the DNA or RNA millions of times so they’re easier to detect. But there’s not yet a quick way to replicate proteins, like antibodies, to make them more detectable.
Robinson explained that he and his team took antigens indicative of thyroid cancer, and added a specific piece of DNA to these antigens, to serve as a marker. Even though they couldn’t replicate the proteins themselves, they could replicate the DNA markers. Antibodies then globbed onto the antigens, which gathered all the marker-DNA together. After a series of chemical reactions, all of the marker-DNA could be copied, and the larger amounts of it indicated the presence of antigens. If the individual wasn’t sick, there wouldn’t be any antigens or marker DNA to replicate.
The researchers found their test was 800 to 10,000 times more sensitive than current tests being used. This means that fewer antigens and antibodies are needed to detect a specific illness. Most of the tests currently available—called immunoassays—involve finding a chemical that binds to antibodies, and then running a series of tests to locate the easier-to-find chemical, as opposed to the lone antibody itself.
So far, there hasn’t been a problem with false positives or negatives, which has plagued thyroid cancer detection methods in the past. The Stanford team is now working to develop this same technique for HIV and Type-1 diabetes.
What’s really unique about this type of detection, Robinson says, is that unlike other cancer-detecting tests that require some radioactive components, this one can be done on-site in hospitals. Instead of taking two to three weeks to confirm a diagnosis, it could theoretically take hospitals two to three hours. Robinson says that the test could be available in the next two years.