Lyme disease test

Lyme disease diagnosis: Wanderröte and tick bite

The most important indicator of a Lyme disease diagnosis is the typical rash at the tick site: the “migrans“(Erythema chronicum migrans) It is considered to be a leading symptom of early Lyme disease and affects most (but not all) patients, so after a tick bite you should keep an eye on the surrounding area for several weeks to write a small note a week in the calendar to check the spot once more, as soon as a skin change is noticed, you should consult a doctor.

Another important criterion for Lyme disease diagnosis is the patient’s reports of one tick bite in the anamnesis conversation. Unfortunately, such a sting often goes unnoticed or is forgotten. But then patients can at least tell their doctor if there is the possibility of a tick bite – perhaps because they often walk in the woods and meadows or work in the garden.

Lyme disease test for antibodies

The Wanderröte and the information of the patient to a (possible) tick bite awaken the doctor so a clear suspicion of Lyme disease. For more detailed clarification, various Lyme disease tests are available. Many of them focus on specific ones antibody against the Lyme disease pathogens (Borrelia).

Antibody detection in the blood

Many of the borreliosis tests available search for specific Borrelia antibodies in a patient’s blood sample. However, such tests are controversialbecause they often do not deliver a safe result. There are several reasons for this:

Such a Lyme disease test can not detect infection until several weeks after infection with the bacterium. Only then has the immune system formed specific antibodies against the borrelia. Therefore, at the time of the characteristic rash, the Lyme disease test may still be negative.

Even otherwise, a negative test result does not necessarily mean that the patient has no Lyme disease. In some people, the immune system produces little or no antibodies to the borrelia. Sometimes this is due to a genetic predisposition, in other cases to a weakened immune system. Even with patients treated with so-called immunosuppressants due to another disease, a Lyme disease test can be wrongly negative. Immunosuppressants are drugs that suppress the immune system (immunosuppressants).

Caution is also advised if a Lyme disease test is positive. All that means is that the patient has been infected with Borrelia at some point in time. However, a one-time antibody test does not tell you if it’s a florid infection (with actual symptoms) or a latent (“hidden”) infection. In the second case, the patient has been infected with Borrelia, but these are kept in check by the immune system so that the disease does not break out. In addition, a Lyme disease blood test can also be positive if the infection is already long ago and has long since healed.

Therefore, a positive borreliosis blood test should be interpreted as a clear indication of Lyme disease only in the context of the patient’s typical ailments and history (tick bite). In the case of nonspecific symptoms such as tiredness, malaise, headache and body aches or fever, a Lyme disease test is not meaningful.

Antibody detection in cerebrospinal fluid

If, due to the symptoms and information from the anamnesis interview the Suspected neuroborreliosis The physician may take a sample of cerebrospinal fluid (CSF) from the patient. This happens as part of a CSF function. In the laboratory, the CSF sample can be tested for antibodies against Borrelia.

More Lyme Blood Tests

There are other variants of Lyme disease tests. One of them is the so-called Lymphocyte Transformation Test (LTT), He does not search for specific antibodies in the blood of the patient, but focuses on specific cells of the immune system: the lymphocytes. To do this, a blood sample of the patient is mixed with parts of Borrelia bacteria. If the lymphocytes proliferate at lightning speed, this means that they have already been alerted by this pathogen – so there is an acute Borrelia infection. In contrast, if the lymphocytes proliferate only slowly due to contact with Borrelia components, the patient does not have Lyme disease.

Of the advantage The lymphocyte transformation test is that it can already indicate a borreliosis infection in the early stages. Of the disadvantage: The test results are not very reliable. Thus, the LTT can also be positive for people who have never been in contact with Borrelia. That’s why this Lyme disease test is done by experts only recommended in certain cases.

Borrelia detection in patient samples

A confirmed diagnosis of Lyme disease, if one the Directly detect Borrelia can, in sample material of the patient. For this, the bacteria are grown from the patient sample. The sample may be from abnormally altered skin, joint fluid (suspected Lyme arthritis), or cerebrospinal fluid (suspected neuroborreliosis). However, such Borrelia culturing from sample material is very time-consuming, takes a lot of time and is only carried out in a few specialized laboratories.

Alternatively one can also use the Proven genetic material of Borrelia instead of the bacteria themselves. The genetic fragments found can be amplified by PCR (polymerase chain reaction) and then detected. This is faster than a Borrelia cultivation. This form of Lyme disease test is performed mainly with samples of joint fluid if the physician suspects Lyme arthritis in the patient.

Borrelia evidence in the tick

Some laboratories offer Lyme disease tests for ticks sent in. Anyone who discovers a sucking tick on his body can remove it and send it to a lab for analysis (or the doctor does it). There it is examined whether in the bloodsucker genome of Borrelia can be found. The detection is usually by means of polymerase chain reaction (PCR), which is why often short of Tick-PCR is spoken. However, many experts consider such borreliosis tests on ticks critical because a positive test result does not allow a clear interpretation:

A positive test result is if Borrelia genome was found in the tick. But that does not automatically mean that the bacteria have been transmitted to humans. That depends, among other things, on the duration of the suction cycle. If an infected tick has been sucking blood on a person for less than 24 hours, the likelihood of Borrelia transmission is very low. The affected person is therefore unlikely to have Lyme disease.

In addition, some laboratories generally test the ticks for the genome of Borrelia burgdorferi sensu lato: This is a large group of closely related Borrelia genospecies, some of which cause Lyme disease, but not others. In a positive tick borreliosis test, the affected tick may therefore only be infected with Borrelia, which does not cause Lyme disease in humans.

Conclusion: The Borrelia detection in ticks is not suitable for making therapy decisions. Because of a positive test result, patients should not be treated with antibiotics.

Conclusion: Lyme disease diagnosis is difficult

Lyme disease can be very diverse in its symptoms and course. This complicates the diagnosis, especially in later stages of the disease. First and foremost, Lyme disease is a clinical suspected diagnosis: this results from the symptoms of the patient, his medical history and various more or less reliable Lyme disease test-Method. In addition, other possible cause of the symptoms must be excluded before the Lyme disease diagnosis is considered certain.