Lyme disease is caused by Borrelia burgdorferi, a bacterium that spreads through certain types of ticks. Find out the tests that should be carried out to diagnose this ailment.
Lyme disease is common in parts of Eastern United States, and this tick-borne disease is transmitted to humans through the bite of deer ticks. Deer ticks are vectors of the bacteria that cause Lyme disease. Symptoms include, tiredness, headache, and in some cases flu-like symptoms like fever and depression. Over 80% of patients develop a skin rash known as erythema chronicum migrans, which appears as a painless, red, rash, typically in the form of a bull’s-eye. The innermost circle turns dark red and the skin turns thicker and may feel warm to touch. If not treated on time, the disease may progress and can cause numbness in limbs, facial paralysis, joint pain, memory loss and, in severe cases, meningitis. If detected early, antibiotics are used for its treatment.
Testing for Lyme Disease
When an individual gets infected by the bacteria, the human body takes a while to actually begin producing antibodies against it. Once produced, these antibodies stay in the human body forever. These are referred to as immunoglobulin M (IgM), and it can take a few weeks before these are detectable by pathological tests. Hence individuals who are in the early stages may not show positive test results. In most cases, people who have been infected for more than a month may have positive test results. There are mainly three types of tests.
IFA (Indirect Immunofluorescence Assay)
This is a test that analyzes and detects Lyme disease antibodies.
ELISA (Enzyme-linked Immunosorbent Serologic Assay)
One of the fastest and most common way to identify the presence of antibodies. This is a more reliable testing method as compared to IFA.
Western Blot Test
This test yields more specific results than the tests mentioned above. It is carried out to confirm the findings only when any of the above tests have yielded positive (even borderline positive) results.
False-negative test results for antibody testing can mean that the human body has not yet made antibodies to fight off the infection, which is possible in early stages. It might also mean that the level of antibodies is too low for the test to detect. Individuals who had taken antibiotics for this disease may also have negative blood test results. Some people who have undergone ELISA testing may also have a false-negative result. This can happen if the individual has been infected with the bacteria from a different region than the one where the ELISA test has been carried out.
In case of positive results, the findings may conclude that the individual is infected if antibodies are detected. This can also signify that the person is currently suffering from the disease, or had suffered from it in the past. Sometimes, results show a false-positive test, which means that the test shows the presence of antibodies, but these are not for Lyme disease, but other bacterial or viral diseases. In case of a positive test result, Polymerase Chain Reaction testing is usually carried out to confirm the presence of this disease.
Polymerase Chain Reaction Testing
This test detects the presence of DNA of the bacteria that causes Lyme disease. This test is carried out for a patient who has not recovered even after antibiotic treatment. But there are limitations to this test. The test can be expensive and requires the use of ultramodern testing equipment and technical expertise. Standard testing procedures have not been developed yet, and the chances of false-positive test results is therefore, high.
Skin Culture Test
In this test, a tissue sample collected from the infected individual is screened for the presence of bacteria. But this procedure takes a few months and hence, is carried out rarely.
All these tests are carried out using blood sample that is collected from a vein in the arm, or by collecting cerebrospinal fluid using lumbar puncture. Even though PCR actually detects the presence of bacteria, other tests are usually carried out more often, even though they only detect the presence of antibodies. This is calculated in terms of titers, higher titers signify the presence of an infection, but lower titers cannot be relied upon if the level of antibodies present is too low.
Lyme disease is usually treated with a dose of antibiotics, and patients treated in the early stages of an infection can get cured completely. But the best way to prevent this disease is to avoid tick bites. If you live in a tick-infested area, wear covered clothing if you enter a wooded area filled with tall grass and plants. If you have recently visited a tick-infested area, check for very small black-legged insects that could be stuck on your skin and clothes. If you find any, carefully grasp it head with a pair of tweezers and pull them apart, taking care not to crush it in the process. Save the insects in a zip-lock pouch. If you have been bitten, wash the skin with antibacterial soap. If you develop any unusual rash, bring it to the notice of your doctor immediately. To get rid of ticks, spray insecticides in your garden, trim overgrown weeds and mow the lawn. Most symptoms of Lyme disease can be confused with symptoms of other ailments as well, so seeking prompt medical advice is the best way to prevent the condition from worsening.