It’s quick to spot a tick, but harder to know if that tick carries Lyme disease.
Emergency room visits for tick bites provide important data for the Centers for Disease Control and Prevention, but doctors often cannot immediately confirm whether a patient has Lyme disease. Blood tests depend on antibodies that typically take about two weeks to develop after infection.
The CDC advises people who find an attached tick to remove it and monitor for signs of infection, though only 70% to 80% of infected people develop a rash. Other early symptoms — including fatigue, fever and headaches — overlap with many bacterial and viral illnesses.
If the patient cannot yet provide clear answers, the tick sometimes can — and that’s where tick tests can come in handy.
These tests analyze the pathogens a tick may harbor. Tick testing uses the same polymerase chain reaction, or PCR, technology used in COVID-19 and flu tests to distinguish whether a tick carries a pathogen. According to the Pennsylvania Tick Research Lab, the technique rapidly copies the DNA and RNA in a tick, allowing scientists to compare those sequences with the Borrelia bacteria known to cause Lyme disease.
“It’s not a diagnosis. It’s not telling you, no, you don’t have Lyme disease,” said Stephen Rich, a professor of microbiology at the University of Massachusetts Amherst and director of the TickReport. “What it’s saying is that tick that just bit you, it had the agent that causes Lyme disease. You may want to think carefully about coming back for that follow up serology.”
TickReport is a professional tick-testing service based in Amherst. Founded at UMass Amherst in 2006, the company later became an independent business offering tests for Lyme disease, Rocky Mountain spotted fever, Powassan virus and other tick-borne illnesses.
Most tick-testing services charge at least $55 for DNA tests, with higher prices for RNA and comprehensive testing. TickReport charges $60 for a DNA test, $100 for combined DNA and RNA testing and $200 for a comprehensive test.
However, the CDC recommends avoiding tick tests because the results will come in too late to take doxycycline or prophylactic antibiotics. Most tick testing requires three business days, which may be too long if a tick encounter occurs on a Friday. Negative results could also be false, discouraging people from following up with a doctor.
Positive results do not mean a person has been infected with Lyme disease. Roughly 50% of adult black-legged ticks and 30% of nymphs carry Borrelia bacteria. Ticks must remain engorged for at least 24 hours to transmit Borrelia, although some experts put the minimum at 36 to 48 hours.
“Let’s say it’s a three- to four-day engorged black-legged tick from Massachusetts, and you might like to know if that tick was carrying the Lyme disease germ, you could send it in to be tested,” said Thomas Mather, “The Tick Guy” and director of The Tick Encounter. “But if it was a tick that looked like it was either loose and wandering on you or your dog, or it looks like it had been attached for less than a day, then you might choose not to spend $100 to have it tested because even if it was an infected tick, the risk of becoming infected is low.”
Mather said tick testing can cause unnecessary worry, even when the tick is not a species known to spread Lyme disease. Many people cannot distinguish between black-legged ticks, lone star ticks and American dog ticks. The latter two species do not transmit Lyme disease, though they can carry other pathogens.
Rather than tests, the Tick Encounter relies on photographs to inform Rhode Island residents about their tick bites. Mather said he gives a reply within 24 hours, allowing people to seek treatment corresponding with the type of tick and the pathogens it harbors.
However, tick testing does more than just contribute to an individual’s understanding of their Lyme disease risk. Unlike with mosquito-borne illnesses, Massachusetts does not conduct statewide surveillance of tick-borne diseases. The data is collected through self-reporting rather than proactive surveys and testing. These passive surveillance data sets, while incomplete, are an inexpensive tools used in scientific studies and public policy.
Tick testing is one way to address the need for more surveillance of tick-borne illnesses. Since its founding, TickReport has tested 144,314 ticks, creating a sizable data set. The company publishes all of its results in a tick-borne Disease Passive Surveillance Database. Over the last year, the company has tested 10,250 ticks and 1,950 tested positive for general Borrelia.
Rich said the data can be somewhat uneven because people must first find, preserve, and send the tick in for testing. Still, he said the results provide valuable insight.
“I do know that we see an increase in things like Powassan virus, but without knowing the underlying sampling, it’s hard for me to say whether that’s statistically meaningful,” Rich said.
Rich and Mather both stress that tick testing does not replace diagnosis, medical attention or personal documentation of symptoms. Rather, it’s another tool to help inform people about elusive tick-borne diseases.
“I think more people are in need of tick testing and maybe haven’t yet realized that TickReport will satisfy what they’re trying to do better than an emergency room or an urgent care,” Rich said.
