Lyme disease occurs when a tick infected with the borrelia bacteria latches on to a host and passes the bacteria into the bloodstream. While not all ticks have Lyme disease, numbers of those that are infected with borrelia continue to rise in popular areas throughout the United States, which leads to an increased risk of contracting the disease. When someone is bitten by an infected tick, it takes roughly 36–48 hours for the tick to pass the bacteria onto its host.
Ticks are small and can be missed if you don’t do proper checks after time spent outdoors. In the even that you are bitten and do contract Lyme disease, you may experience flu-like symptoms, fever, chills, headaches, fatigue, muscle and joint aches, and swollen lymph nodes. A bulls-eye rash may also appear at the site – but what if there is no rash and you are unaware a tick bite occurred at all? If you’re experiencing these symptoms and are worried that you have Lyme disease, you will have to get tested. So what is the most reliable Lyme disease test?
How to test for Lyme disease
There is more than one way to test for Lyme disease. The tests that are most used today include the ELISA and the Western blot test. They are designed to look for evidence that the body has responded to a Lyme disease infection rather than looking for the actual infection itself. The ELISA is typically part one of a two-step process, but it only requires one blood sample to be taken. According to the CDC, the ELISA should be ordered first prior to the Western blot.
ELISA and western blot
The first part of the ELISA test acts as a preliminary investigation to see if further testing is needed. A negative result typically warrants no further testing, but a positive one does. The first test is highly sensitive and the second highly specific. This makes sure that only people with Lyme disease are diagnosed and treated.
The Western blot test is a type of blood test that aims to single out certain proteins known as antigens. It is used to identify an active infection of Lyme disease. Although sometimes accurate, however, this test is inherently flawed because methods and criteria for interpreting results can change from lab to lab.
PCR, antigen detection and culture testing
Other types of tests for Lyme disease include PCR (polymerase chain reaction), antigen detection, and culture testing. These tests look for the bacteria as opposed to the antigens created by your body in response to the bacteria.
A PCR test uses a portion of DNA from the borrelia bacteria to help with detection. Antigen testing looks for a specific protein of the Lyme bacteria to help diagnose Lyme disease and can identify infection in people who have had negative results using the ELISA and Western blot tests.
The final option is culture testing, which is highly regarded as the gold standard for diagnosis. Blood is taken from a person suspected of having Lyme disease, and the lab attempts to grow Lyme bacteria using the blood culture. This test is new, however, and the CDC has exercised caution against using it since there is only one commercially available culture test for Lyme disease.
Testing for Lyme disease years later
When a person doesn’t know that they’ve had Lyme for years and begins presenting with symptoms of a chronic Lyme disease infection, they will likely be tested to look for antibodies. This is because antibodies continue to build up within the system while the infection runs rampant.
How reliable is a Lyme disease blood test?
Although the tests used to diagnose Lyme disease can be highly accurate, the timing with which they are conducted matters a great deal. When a person becomes infected with Lyme, it takes up to six weeks for their body to respond and create the appropriate antibodies to fight it off. In the two-step testing process that looks for these antibodies, detecting Lyme disease before the antibodies have had the chance to develop can be difficult, if not impossible. According to research, over 50% of cases are missed using this two-step process.
The PCR test used to detect Lyme disease bacteria itself is typically highly accurate; however, it can also lead to false negatives in people who do have Lyme disease if its distribution is sparse within the body.
What is the most reliable Lyme disease test?
There is no one answer when it comes to determining which Lyme disease test is the most reliable. This is because each test looks for a different thing at a different stage of the infection. When investigating a long-term infection, tests that look for the body’s response to the infection are the most reliable, whereas for an active infection, a test that identifies the bacteria itself will be the most effective. Some tests only show up on an active infection and fail to indicate chronic Lyme, so the most reliable test option depends on which stage a person’s infection is currently at.