Despite the tendency to rely considerably on laboratory test results f
or the differential diagnosis of Lyme disease, considerable problems e
xist with such testing. In this article we compare the effectiveness o
f five main categories of laboratory tests used for the detection of L
yme disease. Our goal is to enable the reader to better understand the
limitations of different test methods and to realize that until bette
r tests become available, diagnosis of Lyme disease still must be made
clinically. Clinical data, however, can be used to increase the predi
ctive power of any laboratory test as well as to help judge its validi
ty.