Clinical tests and medical investigations for the diagnosis of Lyme disease.
Diagnosis of Lyme disease is based on a detailed history and complete clinical examination, along with specific laboratory tests.
1. Your doctor will ask if you were bitten by the tick and if you develop outdoor activities in endemic areas as known for ticks.
2. Clinical signs are important, especially the presence of erythema migrans, as described above.
- If there is any doubt regarding the causation of rash, the doctor can measure the size of erythema and then ask you to return to perform a second measurement every 2-3 days away. Erythema migrans increase in size about 1 inch every day;
- There are specific clinical signs with which the physician can distinguish Lyme disease from other diseases.
There are two blood tests that can be used to detect Lyme disease, a screening test (ELISA Lyme), and if the result is positive, a specific test (called "Western blot"), which confirms this infection or a previous infection, from the past.In countries where Lyme disease is very common problem, patients may have tested positive for Borrelia, and without having the disease itself. Simple positive screening test is not sufficient to establish the diagnosis of Lyme disease: Western blot and has to be positive, also .
Once the tests for Lyme disease is positive, they remain positive for a large period of time, after appropriate treatment. Thus, to repeat the test after patient treatment is not necessary or useful.
4. Ticks can carry other organisms besides B. Burgdorferi, which can cause diseases that can mimic Lyme disease. Therefore, doctors may recommend liver function tests and blood testing to determine blood counts.
5. Patients who present with headache may require lumbar puncture to determine if there is a degree of inflammation of the nervous system and to detect the possible presence of Lyme disease specific antibodies in cerebrospinal fluid (CSF).
6. Doctors may require electrocardiogram (ECG) to identify potential cardiac complications.
7. Magnetic resonance imaging (MRI) and computer tomography can be performed in order to exclude other diseases with symptoms similar to Lyme disease.