The Centers for Disease Control and Prevention (CDC)’s tests for Lyme disease fall short. This two-tiered test consists of a Lyme Antibody (Ab) Screen followed by a Lyme western blot. First, you take the screen. If that’s positive or equivocal, then you take the western blot. But why do these tests miss the mark?
Reliable blood tests need two things: sensitivity and specificity.
Sensitivity is the ability of a test to include all the people who do have the disease. In other words, someone who has Lyme shouldn’t test negative.
Specificity is the ability of a test to exclude people who don’t have the disease. In other words, people who don’t have Lyme shouldn’t test positive.
The two-tiered test gets high marks for specificity, but low ones for sensitivity.
The Tests’ Sensitivity in Early Lyme Disease
Lyme is most effectively treated in the early stage. Yet that’s when the two-tiered test is least reliable.
In Conquering Lyme Disease, Fallon writes, “The fact that in early Lyme disease the false negative rate is as high as 60 to 70 percent means that the testing is of little use at one of the most important phases of infection—early Lyme disease—when it is most responsive to treatment.”
In other words, when we need an accurate test the most, the two-tiered test fails.
The Tests’ Sensitivity in Late-Stage Lyme Disease
According to a PubMed.gov article, “There is a dramatic increase in test sensitivity with progression of B. burgdorferi infection from early to late LD.”
In other words, the longer you have untreated Lyme disease, the more sensitive the tests.
In defense of that, a New York Times article says, “Dr. Mead of the CDC . . . said . . . the tests . . . are accurate in more than 90 percent of cases of long-term Lyme infection.”
Still, even if that number is accurate, the tests miss ten out of every 100 late-stage Lyme sufferers. Meanwhile, those patients remain undiagnosed and untreated. The Lyme bacteria then has time to multiply, resulting in a more debilitating illness. In contrast, the AIDS test misses only one in 200 cases.
Plus, as Dr. Joseph Burrascano says, “The sicker you are, the less reliable the Lyme tests.”
Why? Because Lyme attacks your immune system, and the standard tests are based on antibodies. In other words, they look for evidence of your body’s defense against the bacteria, not the bacteria itself.
Four Reasons for a False Negative
Let’s say you still have a strong immune system, and you’ve been infected for at least eight weeks. Can you still get a false negative? Yes. Medicine could’ve affected your results, or you may have a different strain of Lyme.
We’ve now discussed some ways the two-tiered test is lacking, but is there a better test? There is! Click here to read my next post!