Lyme Disease Testing Practices, Wisconsin, USA, 2016-2019

Area of Science:

• Epidemiology
• Infectious Disease Surveillance

Background:

• Laboratory diagnostic tests are crucial for monitoring Lyme disease prevalence in the United States.
• Interpreting surveillance data relies heavily on accurate and consistent testing methodologies.

Purpose of the Study:

• To evaluate the impact of repeat laboratory testing on Lyme disease surveillance data.
• To determine the frequency of repeat positive Lyme disease tests and associated demographic factors.

Main Methods:

• Analysis of a national dataset of Lyme disease laboratory results.
• Assessment of repeat testing rates among individuals with previous positive serology.
• Stratification of repeat testing frequency by patient age.

Main Results:

• Between 6% and 15% of individuals with a positive Lyme disease test in a given year had also tested positive in a previous year.
• The likelihood of repeat testing increased significantly with advancing patient age.
• This indicates a notable proportion of positive results may stem from individuals with historical seropositivity.

Conclusions:

• Repeat testing in individuals with prior positive Lyme disease results can introduce bias into national surveillance data.
• Age is a significant factor influencing the frequency of such repeat testing.
• Public health agencies should consider these findings to refine Lyme disease surveillance strategies and data interpretation.