American Board of Internal Medicine (ABIM) Certification Practice Exam

Which condition allows for serologic testing for Lyme disease to be waived?

1. Single erythema migrans at site of inoculation

2. Multiple erythema migrans

3. Severe fatigue

4. Persistent headache

The correct answer is: Single erythema migrans at site of inoculation

The condition that allows for serologic testing for Lyme disease to be waived is the presence of a single erythema migrans at the site of inoculation. Erythema migrans is a hallmark skin manifestation of Lyme disease and is considered a major clinical criterion for diagnosis. When a clinician observes a single erythema migrans lesion in a patient with a history of potential exposure to ticks in a Lyme-endemic area, the diagnosis can be made clinically without the need for further serological confirmation. In such cases, the characteristic appearance of erythema migrans, along with the clinical context, provides sufficient evidence to proceed with treatment for Lyme disease, particularly with early intervention. Consequently, the reliance on serologic tests, which can sometimes yield false negatives or take time to become positive, is not necessary when the clinical presentation is clear and unmistakable. Other choices involve symptoms or findings that are not as diagnostic. Multiple erythema migrans lesions might strengthen the suspicion of Lyme disease, but they don’t directly allow for waiving of serology; it would still warrant further investigation. Severe fatigue and persistent headache are nonspecific symptoms that can occur in a variety of conditions, including but not limited to Lyme disease, and therefore do not qualify