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06/05/2008 06:10 AM

Western Blot Test

Posts: 243

Hi Everyone. I have been reading a lot of posts from people saying they were misdiagnosed with fibromyalgia where in fact they had lymes disease. People have been saying to get awestern blot test and I am not sure where you get these tests done. Do I ask my doctor to send me for it? I was tested for lymes disease back in October, but it came back negative. I am not sure what type of test they did, but I wasn to look into this Western Blot test. I already reached my deductable for my insurance, so it would be free. Thanks!

06/05/2008 06:53 AM
Posts: 93

Isn't the western blot test another name for HIV testing? Just curious to know myself.

06/05/2008 07:34 AM
Posts: 284

IgeneX Labs does the Western Blot, see link to their website below. Have your doctor contact them directly on instructions for shipping blood for testing.


The IgG Western Blot is a sandwich-type immunoassay performed in a manner that allows visualization of the patient's antibodies. It is a qualitative test and is generally more sensitive and specific than the ELISA. This test must be used if the Lyme IgG/IgM antibody serology is equivocal or positive. The somewhat-specific Lyme antibodies of importance are against the following molecular weights of the B. burgdorferi antigens: 23-25 kDa (Osp C); 31 kDa (Osp A); 34 kDa (Osp Cool; 39 kDa; 41 kDa; and 83-93 kDa7. "kDa" is the abbreviation for "kilodalton," which is used for molecular weight designations. "Osp" refers to outer surface protein of the bacteria.

There are currently multiple criteria that support a positive blot. "Positive" means that certain antibodies to B. burgdorferi are present. The CDC/ASTPHLD criteria are very conservative, require 5 of 10 bands (antibodies) for a positive result, and do not recognize equivocal or borderline results.8,9 These criteria would be more appropriate for a formal clinical study during early Lyme disease.

IGeneX has several years of clinical data that support more liberal reporting criteria.10 In addition, current studies show that the CDC/ASTPHLD criteria miss some patients with culture-proven erythema migrans (EM).5,11 Both the IGeneX and the CDC/ASTPHLD criteria are included on the IGeneX report form sent to the physician. 3,5,8,9

The Western Blot involves a highly complex visual determination of protein bands, based on their molecular weights and intensities. The IGeneX report form provides an interpretation along with the results in detail.

A positive IgG result with clinical history may be indicative of Lyme disease. Patients with other spirochetal disease and/or who test positive for rheumatoid factor or Epstein Barr virus may have cross-reacting antibodies. A positive response in this, as in any antibody assay, indicates sensitization, not necessarily active disease. 12

Figure 4. Significant antibodies detected by Western Blot (Lane 1 has kDa marker proteins)


The IgM Western Blot is a very sensitive indicator of exposure to B. burgdorferi. It may be positive as early as one week after a tick bite, and will usually remain positive for six to eight weeks after the initial exposure. Re-exposure and recurrent disease also cause this test to be positive for a period of time. For the testing to be complete, the IgM blot should be run along with the IgG blot. However, for economic reasons, the IgG blot may be run first: when the IgG blot is negative, the IgM blot should be performed.

The antibody specificities of importance for the IgM blot are similar to those for the IgG blot (with the exception of 83-93 kDa, which is still being investigated for significance). The CDC/ASTPHLD criteria for a positive result are two of the following three bands: 23-25 kDa (Osp C); 39 kDa; and/or 41 kDa.8,9 IGeneX adds the 31 kDa (Osp A), and/or the 34 kDa (Osp Cool to the criteria,10,12 with the argument that these two antigens are used for the vaccines and therefore their antibodies should be included in the interpretation of positivity. The IgM Western blot is often positive in patients with persistent infection.6 Sometimes it is the only antibody marker detected.

When the IgM ELISA is equivocal or positive, the IgM Western blot must be performed. In addition, because the literature suggests that rheumatoid conditions may lead to false positive IgM antibody responses, an ANA/DNA/rheumatoid factor screen may be ordered to rule out false positive reactions. Patients testing positive with serologic tests for syphilis may also test positive for the Lyme antibody tests.13-15

A positive IgM result with clinical history may be indicative of early Lyme disease or persistent infection in otherwise serologically negative individuals. Recently reported data support our observation that some Lyme patients may have only a restricted IgM response to B. burgdorferi. 16,17

Similar to the IgG Western blot, the IgM Western blot involves a highly complex visual determination of protein bands, based on their molecular weights and intensities. For both tests, IGeneX uses multiple negative controls to serve as baselines for comparison to positive responses.

The IGeneX report form provides an interpretation along with the results in detail.

IGeneX, Inc.

795 San Antonio Rd., Palo Alto, CA 94303 USA

Tel. 650.424.1191 / 800.832.3200 Fax. 650.424.1196


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