Immunoblot tests for Lyme disease testing can detect two different classes of antibodies: IgM and IgG. IgM antibodies are made sooner, so testing for them can be helpful for identifying patients during the first few weeks of infection. The downside of testing for IgM antibodies is that they are more likely to give false positive results. Tests for IgG antibodies are more reliable, but can take 4-6 weeks for the body to produce in large enough quantities for the test to detect them.
If this sounds complex, that’s because it is. Just remember the following:
- The immunoblot should not be run without first performing an EIA or IFA.
- The immunoblot should not be run if the EIA or IFA tests are negative.
- A positive IgM immunoblot is only meaningful during the first 4 weeks of illness
- If you’ve been ill for longer than 4-6 weeks and the IgG immunoblot test is negative, it is unlikely that you have Lyme disease, even if the IgM immunoblot is positive.
All specimens positive or equivocal by a sensitive EIA or IFA should be tested by a standardized Western immunoblot. Specimens negative by a sensitive EIA or IFA need not be tested further.
When Western immunoblot is used during the first 4 weeks of disease onset (early LD), both immuno- globulin M (IgM) and immunoglobulin G (IgG) procedures should be performed. A positive IgM test result alone is not recommended for use in determining active disease in persons with illness greater than 1 month's duration, because the likelihood of a false-positive test result for a current infection is high for these persons.
If a patient with suspected early LD has a negative serology, serologic evidence of infection is best obtained by testing of paired acute- and convalescent-phase serum samples. Serum samples from persons with disseminated or late-stage LD almost always have a strong IgG response to Borrelia burgdorferi antigens.
An IgM immunoblot be considered positive if two of the following three bands are present:
- 24 kDa (OspC)
- 39 kDa
- 41 kDa (Fla)
It was further recommended that an IgG immunoblot be considered positive if 5 of the following 10 bands are present:
- 18 kDa
- 21 kDa
- 28 kDa
- 30 kDa
- 39 kDa
- 41 kDa
- 45 kDa
- 58 kDa (not GroEL)
- 66 kDa
- 93 kDa (2).
But what about IgeneX? In the mid-1970s, the FDA began exempting certain diagnostic tests from its approval process. Many of these tests — developed, manufactured, and offered by a single lab, such as in a hospital — were variations on common tests, low-risk, or devised for rare diseases and could not be adequately validated. They were called “lab development Tests.”
But companies are using this exemption to market thousands of these so-called lab development tests — for everything from cancer to genetic markers of disease — and many have not been rigorously validated. The labs do not market these tests directly to the public; doing so would trigger stricter FDA review. Instead doctors order the tests for patients.
In the case of IgeneX, while the lab itself is FDA-approved, the tests they do are NOT. They use a proprietary Western Blot and use additional “bands: 23, 31, 34, 37, 39, 23-25, 83-93. They also report IND bands. They don’t offer an interpretation beyond claiming these are Lyme specific, leaving the interpretation up to the provider. Some look at 18 23 30 31 34 37 39 83 93. Other doctors focus on 23-25, 31, 34, 39, 83-93. And far too many “LLDs” interpret any banding as enough evidence to treat.
The difficulty is NONE of those bands have been proven to be “lyme specific” (yet). In fact many of them overlap with many infections, leading to the “co-infection” theory. Few legitimate physicians will use these tests, because the additional bands provide NO useful or relevant information. It is often times difficult to find a legitimate phlebotomist to even draw for them.
Some independent labs are working hard to prove their tests' validity. Responsible labs will look for outside validation of their tests. In the meantime, patients can fall prey to a complicated system and a lot of misinformation, because most are like IgeneX. “You need a ton of documentation, time, and money," says Jyotsna S. Shah, vice president of IgeneX, a lab that performs more than 25,000 Lyme tests a year at a thousand or more dollars each. IgeneX has published one paper, in an alternative medicine newsletter back in 2007.
The Western Blot, whoever runs it, has limited value in any event. It is hardly diagnostic, but rather only confirms what other tests and symptoms present. The presence of antibodies only indicates a person has had Lyme. It cannot confirm active disease. Once a person has had lyme, they will ALWAYS have positive bands.
These positive bands have developed an entire industry of “lyme literate” practitioners in the U.S. In addition to 131 million dollars of meaningless tests each year, the industry collects on average 10,000 per patient/year, for a 90 billion dollar a year industry. IV antibiotics alone are $18 Billion, costing thousands a month out of pocket. All based on non standardized/non proven testing.