What is lyme disease?
Lyme disease is one of the commonest tick born diseases in the United States and is caused by several bacteria belonging to the genus, Borellia. Among them, Borellia burgdoferi is the commonest and the tick that transmits the disease is known as the ‘hard tick’ which belongs to genus Ixodes.
What are its symptoms?
The presenting symptoms of Lyme disease are almost similar to many types of other illnesses and therefore the diagnosis would be rather difficult. Among the most common symptoms, fever, headache, depression, fatigue…etc along with a characteristic rash which appears like a ‘bull’s eye’ is also called erythema migrans.
Therefore, in order to make an accurate diagnosis, one must make use of several tests which will be on blood, tissues, cultures or else on cerebro-spinal fluid.
What can be detected in a lyme disease patients?
In most of the infection, once a bacteria or a virus enters the body the immune system will respond by forming antibodies. These antibodies will take time to develop and it may vary from few days to several weeks. Following formation of these antibodies, it can be detected in the blood and there would be two types of antibodies named as IgG and IgM. Among these two antibody types, the IgM would represent an acute infection and will diminish with time whereas the IgG antibodies might form late and will be present for a prolonged duration.
Thus, the detection of specific types of antibodies would indicate to the physician regarding the possibility of that particular infection and then a rough estimate as to when it was contracted. But, it should be kept in mind that, these tests should be interpreted with the clinical findings as there is a chance of these tests leading to false positive results.
As described before, such antibodies will be formed in patients with lyme disease as well and the blood tests that will be described next would make use of this fact to confirm a diagnosis.
What are the specific tests for lyme disease performed on blood?
There are specific blood tests performed in patients with lyme disease and two of them are the Enzyme Linked Immuno Sorbent Assay (ELISA) or Indirect Fluorescent Antibody (IFA) test.
Among these tests, the ELISA is one of the commonest tests used for making a diagnosis for lyme disease and would be a cheap and a quick technique to detect serum antibodies. Similarly, the IFA is also used in making a quick diagnosis but both these tests would not be able to detect an acute condition as they may not detect antibodies till several weeks from its initial symptoms.
Following making identification through serum antibody tests, they can be subjected to other tests such as western blot which can further confirm the diagnosis made by indirect tests.
Apart from the above tests, the blood can be subjected to culture for direct tests as well.