Diagnosis of Lyme disease

If you have the characteristic rash typical for Lyme disease it should not be necessary for the doctor to do any tests – the doctor will treat you with a course of antibiotics.

Laboratory confirmation in people with erythema migrans rash is not recommended because (i) the presentation is sufficient to make a clinical diagnosis and (ii) the antibody response takes several weeks to reach detectable levels therefore antibody tests in the first few weeks of infection may be negative [66].

If you have symptoms suggestive of Lyme disease and a history of being bitten by a tick or of being outdoors in an area that ticks may live the doctor will take a sample of your blood and send it to be tested for Lyme disease.

The most commonly used tests for Lyme disease are tests that look for antibodies to Borrelia burgdorferi, the organism that causes Lyme disease. An infected person’s immune system produces antibodies to Borrelia burgdorferi. These antibodies are one of the mechanisms the body uses to fight the infection. The antibody response takes several weeks to reach a detectable level, so antibody tests in the first few weeks of infection may be negative; hence the need for repeated testing in some cases. It is rare for patients to have negative antibody tests in long-standing infections.

If the sample tests positive for Lyme disease, the doctor will give you a course of antibiotics. If the test result is negative and your symptoms do not get better after 3 or 4 weeks your doctor may repeat the test for Lyme disease.

Laboratories for Lyme disease testing in Scotland and England

Laboratory testing for Lyme disease in Scotland is carried out at the Scottish Lyme Disease and Tick-borne Reference Laboratory (SLDTRL) which is within the Microbiology Department of Raigmore Hospital, Inverness.

In England testing for Lyme disease is carried out at Public Health England’s Rare and Imported Pathogens Laboratory (RIPL), Porton Down, Wiltshire, Salisbury

Laboratory tests for Lyme disease

Information about laboratory tests for Lyme disease[66]

It is important that tests for Lyme disease are carried out at laboratories that:

• Have been accredited by the UK accreditation service (UKACS)
• Use validated tests
• Participate in a formal external quality assurance programme

Tests for Lyme disease have their limitations and false negative and false positive results can occur:

• If a patient’s test results are negative and symptoms persist, they will be assessed for an alternative diagnosis
• The symptoms and signs associated with Lyme disease overlap with those of other conditions
• Symptoms such as tiredness, headache and muscle pain are common and specific medical causes may not be found

Information on testing for Lyme disease

Lyme is usually diagnosed by serology.
RIPL uses a 2-tier testing methodology:

• Screening test is a C6 antigen based ELISA (combined IgG and IgM),
• Followed by a confirmatory Western blot (separate IgG and IgM).

Sensitive screening tests are used because they can detect low levels of antibiotics however, they have the disadvantage of producing false positive results in samples from some patients with other conditions. These include glandular fever, syphilis, other infections, rheumatoid arthritis, other autoimmune conditions and some neurological conditions. Samples that give reactive or indeterminate screening test reactions are then tested in a more detailed system – Immunoblot or Western blot. This permits a more accurate assessment of the presence of Borrelia burgdorferi antibodies.[79]
Polymerase chain reactions (PCR) are also available and may be useful in testing joint fluid and biopsies of rashes. It has poor sensitivity on cerebrospinal fluid (CSF) and antibody detection is the preferred first line test on CSF.
PCR are not usually performed on blood as the duration of bacteraemia is short.