New DNA test to detect Lyme disease spirochete infection

Published on March 30, 2010 at 4:14 AM · No Comments

Many of the more than 30,000 people a year in the United States with suspected cases of Lyme disease spirochete (bacterial) infection can now take a DNA test developed by a Connecticut scientist/physician and his team that can quickly determine if they test positive for Lyme spirochetes in their blood. This is the first such early Lyme test available, and most insurance companies have already agreed to cover the cost for their members.

“said Connecticut physician Sin Hang Lee, MD.”

The scientific medical paper about the advanced test will be printed in the April 2010 edition of the "American Journal of Clinical Pathology."

"If people are infected with the Lyme spirochetes, and not treated quickly, thousands may suffer for many years from the debilitating effects of the disease. "But if, after infection, the bacteria are identified without delay, the patient can be effectively treated and totally cured," said Connecticut physician Sin Hang Lee, MD.

There have been other PCR tests for early Lyme disease. But this is the first effective one using nested PCR for detection and DNA sequencing to validate the molecular diagnosis, in clinical laboratory medicine. DNA sequencing is accepted as the gold standard for molecular identification, said Dr. Lee.

Dr. Lee, a pathologist, and his colleagues at Milford Hospital (Milford, CT) have developed the first highly sensitive and specific DNA test for the diagnosis of early Lyme disease before the traditional serology lab tests become positive. If the clinician awaits the rising Lyme disease antibody titers (which is normally the case) to make a diagnosis, the diagnosis of Lyme disease may be delayed, or even missed. The literature reports that up to 75% of the patients with acute-phase Lyme disease are negative for the characteristic antibodies, but in fact the percentage is higher, he said.

Lyme disease is spread by black-legged ticks, also known as deer ticks, and is most common in Connecticut, Massachusetts, Maryland, Minnesota, New Hampshire, New Jersey, Delaware, Pennsylvania, New York and Wisconsin, according to the Centers for Disease Control. The spirochete bacteria enter the skin at the location of the tick bite. After an incubation for 3-30 days, the bacteria travel through the skin and may spread to lymph nodes or travel through the bloodstream to other organs and other skin sites.

In technical terms, the new LoTemp® nested polymerase chain reaction (PCR) method detects a genomic DNA of the Lyme disease-causing spirochete in the blood, which is further validated by DNA sequencing. It is the marriage of both that minimizes false-negatives to the lowest possible and eliminates false-positives known to be associated with other Lyme disease DNA tests. Symptomatic patients visiting the emergency department or the walk-in center have the best chance for an early diagnosis by this new test. The waiting for a scheduled visit to the doctor's office usually misses the window of opportunity in DNA detection at the time when the bacteria are circulating in the blood of the patient in early Lyme disease, but only briefly, said Dr. Lee.

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