Lyme Disease Borrelia burgdorferi

Category:

Lyme Disease (Borrelia burgdorferi), PCR

Description

A Lyme disease test detects antibodies to the Lyme disease bacteria Borrelia burgdorferi in blood. Lyme disease bacteria are spread by certain kinds of ticks.

Lyme disease can be hard to diagnose because its symptoms are similar to those of many other illnesses.

It may take up to 2 months after becoming infected before antibodies can be detected in a normal blood test. Once formed, antibodies usually stay in the body for many years, even after successful treatment of the disease.

There are three types of antibody Lyme disease test:
- Enzyme-linked immunosorbent assay (ELISA). Common and rapid test to identify Lyme disease antibodies.
- Indirect fluorescent antibody (IFA).
- Western blot test. This test also identifies Lyme disease antibodies and can confirm the results of an ELISA or IFA test.

Antibody testing should be done in a two-step process, using either the ELISA or IFA followed by the Western blot test. ELISA is considered a more reliable and accurate test than IFA, but IFA may be used if ELISA is not available. The Western blot test (which is a more specific test) should be done in all people who have tested positive or borderline positive in an ELISA or IFA test.

Its concentration is measured by means of analysis of a blood sample drawn from the vein in the arm. Antibody testing may also be done on fluid from the spine or from a joint.

Purpose of the test

A Lyme disease test is done to diagnose Lyme disease in people who have symptoms that include:
- Expanding red rash with a pale center.
- Extreme tiredness.
- Fever.
- Headache and stiff neck.
- Muscle and joint pain.

Symptoms of chronic Lyme disease include joint pain, stiffness, and problems with the heart, brain, or nerves.

Reference range values

The results of a Lyme disease test (ELISA, IFA, Western blot) may be reported in titers. A titer is a measure of how much the sample can be diluted before the antibodies to the Lyme disease bacteria can no longer be detected.
A titer of 1 to 8 (1:8) means that antibodies can be detected when 1 part of the blood sample is diluted by up to 8 parts of a salt solution (saline).

Normal (negative):
- For the IFA test, the titer is less than 1:256.
- Polymerase chain reaction (PCR) test does not find any Lyme disease bacteria DNA.

Abnormal (positive):
- For the IFA test, the titer is equal to or greater than 1:256.
- Polymerase chain reaction (PCR) test detects Lyme disease bacteria DNA.

Abnormal findings

An abnormal, or positive, test for Lyme disease can mean:

- If antibodies are found, Lyme disease is present now or was in the past. Antibodies to the bacteria will usually stay in the body for the rest of life.
- If Lyme disease bacteria DNA is found, active Lyme disease infection is present.
- Sometimes an antibody test for Lyme disease finds antibodies to other bacteria, such as syphilis, or viruses, such as the Epstein-Barr virus or the human immunodeficiency virus (HIV).

The PCR test must be done to confirm an infection in case of a positive antibody test result.