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Resources for Clinicians

Diagnosis, Treatment and Testing

Learning Tools


Two-tier testing for Lyme disease

About This Figure

The Two-tier Testing Decision Tree describes the steps required to properly test for Lyme disease. The first required test is the Enzyme Immunoassay (EIA) or Immunofluorescence Assay (IFA). If this test yields negative results, the provider should consider an alternative diagnosis.  Or in cases where the patient has had symptoms for less than or equal to 30 days, the provider may treat the patient and follow up with a convalescent serum. If the first test yields positive or equivocal results, two options are available: 1) if the patient has had symptoms for less than or equal to 30 days, an IgM Western Blot is performed; 2) if the patient has had symptoms for more than 30 days, the IgG Western Blot is performed. The IgM should not be used if the patient has been ill for more than 30 days.

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Understanding laboratory test results

About This Figure

Understanding Test Results for Infectious Diseases

The illustration depicts the likelihood of false positive and false negative test results based on the prior probability of a disease occurring in a given population. Clinicians should consider the likelihood of disease before performing laboratory testing. The likelihood that a patient has a disease depends on many factors:

  • Has a patient been in an area where the disease is found?
  • Does the patient have signs and symptoms typical of the disease?
  • Does the patient have risk factors for contracting or developing the disease?

In populations where disease is rare or unlikely, testing is likely to lead to false positives more frequently than true positives.

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Continuing Medical Education for Clinicians

Lyme Disease Self Assessment

From the American College of Physicians (ACP) Initiative on Lyme Disease--an online quiz containing six clinical scenarios regarding the evaluation and treatment of Lyme disease.

Case Definition and Report Forms

Note: Surveillance case definitions establish uniform criteria for disease reporting and should not be used as the sole criteria for establishing clinical diagnoses, determining the standard of care necessary for a particular patient, setting guidelines for quality assurance, or providing standards for reimbursement.