Lyme Disease: In-office testing and clinical applications

Regardless of where you practice or the month of the year, Lyme disease is prevalent. It is also an incredibly complex ailment and many afflicted patients go undiagnosed for months or years, are subject to inaccurate findings, and/or receive ineffective treatment. This need not be the case.

According to the Centers for Disease Control, Lyme disease is the most-commonly reported vector-born illness in the United States with more than 33,600 cases reported in 2018. However, the CDC readily admits that only 10 percent of Lyme cases are diagnosed and reported properly, meaning that in all likelihood there were in fact 336,000 cases of Lyme in 2018. That would make Lyme the third-most prevalent infectious disease behind Chlamydia and gonorrhea.

As America slowly reopens from months of lock-down, the outdoors will be filled with hikers, campers, hunters, and fishermen. Regrettably, the presence of these outdoor enthusiasts coincides with the annual start of Lyme season and an increased appearance of deer ticks which may be carrying the bacterial infection that spreads Lyme disease to humans and pets.

Physicians need to keep Lyme on their list of things to check for, and ask all patients about, as part of a routine visit. If caught early, Lyme disease is relatively easy to treat, usually with a few weeks of antibiotics. But if missed, it can become a chronic illness that can cause a great deal of suffering for patients.

Spirochete transmission was once thought to occur within 24-36 hours after the tick was embedded under the patient’s skin. We know now that’s not the case and that the disease can be transmitted in 15 minutes or less. We also now know that once the infection begins to spread it becomes more and more complicated and begins to affect new areas of a person’s body. When that happens, the patient begins to present with more systemic symptoms that become challenging to diagnose.

Those who are bitten by an infected tick will start to show varying symptoms, depending on where the infection is localized. Early warning signs include fever, headache, fatigue, joint pain, swollen lymph nodes, weakness in the limbs and sometimes a characteristic skin rash in a bull's-eye pattern. If untreated, new symptoms could include neurological problems and, though less common, heart problems (such as an irregular heartbeat), eye inflammation, liver inflammation and severe fatigue. 

One of the challenges for consumers and physicians alike is that unlike a mosquito bite where people know immediately if they have been bitten, Lyme disease symptoms often will not appear for 2-6 weeks and only about 25 percent of patients even recall getting a tick bite. The other complication is that Lyme disease presents differently from person to person, making it arduous to detect. 

Fortunately, new tools are now available to make it easier to test for Lyme disease quickly and accurately. The best tool I have found, which has basically revolutionized the speed and accuracy for diagnosing Lyme disease, is the Sofia 2 Lyme FIA test by Quidel Corporation. CLIA-waived, this rapid in-office test went through extensive clinical trials for accuracy and is now an invaluable part of my practice. It provides a patient and physician with indicative results within minutes as opposed to days, which has historically been the norm. Additionally, it’s the only test that can get results from a simple finger prick of blood-other tests require being sent out for centrifuging. A medical assistant or nurse simply does a finger prick, puts the blood sample on a cassette and inserts it into the Sofia 2 analyzer. Within minutes, positive or negative findings merge.

If the test comes back positive, the patient can be treated with 1-2 months of antibiotics or sent out for a step 2 test. But further testing means delaying treatment while organisms spread and become systemic disease, so that is not always advisable. If the test comes back negative, which is the case in a vast majority of patients, we can more quickly pursue other diagnoses and treatments for patients experiencing worrisome signs (there are other species of borrelia and other tick-bone diseases can closely mimic symptoms of Lyme). Also consider the timing. It may take several weeks after a tick bite to produce enough antibodies to be detected, so consider repeating a Sofia 2 Lyme test in 2-4 weeks if suspicion is high.

One of the tricky parts is that negative testing does not necessarily mean the patient does not have Lyme disease. Many Lyme disease patients never make enough antibodies to have a positive test which results in a “False Negative.” If your patient has all the findings of Lyme disease and you have ruled out other diseases that can cause those same symptoms, there is a high likelihood that patient actually has Lyme disease, and you should consider empirical treatment.

In the final analysis, the best tool a physician has is his or her own brain. Learn to think critically, know that Lyme can present differently in different patients, and keep Lyme high on your checklist for every patient who walks through the door. The fact that clinicians are missing the diagnosis 90 percent of the time means we need to be progressive in our thinking and actions.

About the Author

Sean McCloy, MD, MPH, MA, practices internal medicine with an expertise in Lyme disease at Integrative Health Center of Maine in Portland, Maine