Screening for Lyme Disease

by ]]>Editorial Staff And Contributors]]>

The purpose of screening is early diagnosis and treatment. Screening tests are usually administered to people without current symptoms, but who may be at high risk for certain diseases or conditions.

General Screening Guidelines

At this time, routine screening for Lyme disease is not recommended if you have no symptoms.

The following diagnostic tests may be used in certain situations, such as when a person has no symptoms, but has had an attached tick for some length of time (48 hours or more).

Diagnostic Tests

Antibody Tests

Antibodies are the body’s defense against an infection. If you have been infected with the Lyme disease bacteria, your body will release specific antibodies to fight it. It takes about four weeks or more for these antibodies to become detectable. Examples include:

Antibody titer (ELISA or IFA)—This test measures the level of Lyme disease antibodies in the blood.
Western blot —This test detects the presence of specific antibodies to Lyme disease in the blood and supports the ELISA test results

Both of these tests can have false negative results (the test is negative even though you are infected) or false positive results (the test is positive even though you are not infected).

Some reasons why false negatives may occur include:

The test is performed too soon after infection.
Too few or no antibodies are made.
The test is performed incorrectly.

Some reasons why false positives may occur include:

The test is performed incorrectly.
Your immune system produces unrelated antibodies, which appear to the test as if they were produced in response to Lyme disease.

Direct Detection Tests

These tests look directly for the bacteria, or pieces of it, in the blood and other fluids of the body, such as urine and spinal fluid. Two main types are:

Antigen detection tests—These look for a unique protein from the Lyme disease bacteria that may be in body fluids. This test is useful for detecting Lyme disease in certain situations, such as:
- If you are taking antibiotics
- During a later flare-up of symptoms
Polymerase Chain Reaction (PCR)—This test can multiply the number of pieces of the bacteria in the test fluid, making it easier to detect.

References:

Lyme disease. Lyme Disease Foundation website. Available at: http://www.lyme.org/otherdis/ld.html . Accessed October 5, 2008.

We want you to know about Lyme disease: it's difficult to diagnose. US Food and Drug Administration website. Available at: http://www.fda.gov/cdrh/consumer/lymedisease.html . Updated July 1999. Accessed October 5, 2008.

Last reviewed August 2008 by ]]>David L. Horn, MD, FACP]]>

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.