Lyme Lab Tests Explained

List of Western Blot Bands and Explanations

(from various sources)

9 cross-reactive for Borrellia

12 specific for Bb (Lyme)

18 flagellin fragment (Lyme)

20 may be cross-reactive for Borrellia

21 unknown

22 specific for Bb, probably really the 23/25 band

23-25 outer surface protein C (OspC), specific for Bb. Can be an early band.

28 OspD. Specific for Bb (Lyme).

[23-28] Potential for Central Nervous System (CNS) involvement.

30 OspA- substrate binding protein- common in European and

one California strain. Check for mycoplasma.

31 OspA, specific for Bb (Lyme).

34 outer surface protein B (OspB); specific for Bb (Lyme).

35 specific for Bb

37 FlaA gene product- specific for Bb (Lyme).

38 cross-reactive for Bb

39 BmpA- a major protein of Bb flagellin; specific for Bb- Sometimes found in those with joint involvement. It is the most specific antibody for borreliosis of all bands.

41 flagellin protein of all spirochetes. This is usually the first to appear after a Bb infection and is specific for all Borrellia. Can be positive due to relapsing fever, oral spirochetes and syphilis. Flagella or tail protein. Flagella is used to move Borrelia burgdorferi from point to point. Many bacteria have flagella. This is the most common borreliosis antibody.

45 cross-reactive for all Borellia (sometimes people with Lyme who have

this band positive also have the co-infection Ehrlichiosis). Heat shock protein. This helps the bacteria survive fever. The only bacteria that does not have heat shock proteins is Treponema pallidum, the cause of syphilis.

50 cross-reactive for all Borrellia

55 cross-reactive for all Borrellia

57 cross-reactive for all Borrellia

58 unknown but may be a heat-shock Bb protein- Check for viral infections

60 cross reactive for all Borrellia

66 Oms66- cross-reactive for all Borrelia, common in all bacteria- Check for E-coli

83 high molecular mass protein. Specific antigen for the Lyme bacterium. This is the DNA or genetic material of Borrelia burgdorferi. It is the same as 93, based on medical literature. Laboratories vary in assigning significance to the 83 versus the 93 band.

93 an immunodominant protoplasmic cylinder antigen, associated with the flagellum. Possibly the same protein as in band 83, just migrates differently in some patients.


When reporting bands, the reporting laboratory marks bands with the following indicators of intensity:

Other bacteria besides Borrelia burgdorferi may produce the 45, 58, 66, and 73 kDa bands.

Some patients might have an IgM response at the time of the EM rash. The IgG response tends to start several weeks after infection and peak months to years later. In some patients, the IgM response can remain elevated- in others it might decline, regardless of whether or not treatment is successful.

Many Lyme disease experts believe it is a mistake to exclude 31 and 34 kDa antibody proteins from the list of significant bands.

Lyme disease patients may not test positive for exposure to B. burgdorferi because their antibodies to the organism are bound up in immune complexes.

An indeterminate number of patients with late or chronic Lyme disease are simply seronegative for unknown reasons.