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Another diagnostic technology rapidly gaining ground is the use of DNA, RNA, or nucleic acid probes. This technology, also called molecular diagnostics, involves using specific, short nucleic acid sequences to bind and detect the presence of genetic material. Currently a $500 million-per-year market, it is the fastest growing in vitro diagnostics segment, U.S. Bancorp Piper Jaffray reports, and is forecast to grow 25% per year during the next few years. Blood screening--a $775 million-per-year market growing at 6% per year--is anticipated to be a high-volume application.
Diagnostics have developed in waves of technology, "The first wave was chemical, the second wave enzyme, third wave immunoassay, and the fourth wave is probe technology," he says. "We're in the phase that immunoassays were in the early 1980s--that is, a small number of tests, a lot of people working on the technology, a lot of interest in things coming out, and very aggressive growth. We'll see a significant number of tests available in the next five years."
DNA probe technology has shifted over the past five years from a research tool to clinical diagnostic applications. Infectious disease detection is the largest use, and tests for sexually transmitted diseases, tuberculosis, and pneumonia, as well as for human immunodeficiency virus (HIV) and hepatitis, are available now. Combined with DNA or RNA amplification technologies to increase the viral genetic material to be tested, nucleic acid probes can be used on samples that are difficult to culture or too small to be analyzed by other means. Nucleic acid probes are competing with other means of detecting infectious diseases that include staining and microscopic inspection; microbiology, which involves culturing organisms in growth media; and immunoassays, which use enzymes for antigen or antibody binding followed by detection. Although probe techniques can require more sample preparation, they are extremely sensitive. Relative times for testing depend on which methods are compared. Co has transcription-mediated amplification.
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