Can a positive Lyme disease western blot strip test be mistaken for another disease?

Yes! No lab test is perfect, including the westen blot for lyme. There is an approximately 4% chance of a positive being a "false positive" test. There is also an approximately 20% chance of false negatives, someone with lyme not having a positive western blot. This is why lyme is ultimately a clinical diagnosis, with labs used to support a diagnosis. Other tests may also be useful. Please see comment:.