TABLE 2.
Type of serological laboratory evidence of infection and percent of records classified as confirmed and probable cases among seven states with high incidence of Lyme disease, 2012–2018a
| State | Two-tier IgM |
Two-tier IgG |
Single-tier IgG |
|||
|---|---|---|---|---|---|---|
| Percent confirmed (range) | Percent probable (range) | Percent confirmed (range) | Percent probable (range) | Percent confirmed (range) | Percent probable (range) | |
| 1 | 37.8 (31.8-46.4) | 12.9 (11.7-15.2) | 36.6 (33.7-41.7) | 12.5 (9.7-16.0) | 30.4 (28.3-33.3) | 10.0 (7.7-14.4) |
| 2 | 27.7 (24.1-34.4) | 15.1 (12.4-18.4) | 37.0 (28.8-42.9) | 18.2 (13.5-22.6) | 31.6 (25.7-37.2) | 15.5 (10.4-19.5) |
| 4 | 38.8 (34.6-43.1) | 26.4 (23.3-30.5) | 34.9 (31.8-38.4) | 29.8 (23.9-35.1) | 22.6 (20.9-24.3) | 27.2 (22.4-34.8) |
| 5 | 34.4 (28.5-39.0) | 23.1 (18.4-27.0) | 32.7 (22.6-37.8) | 32.3 (19.8-39.4) | 34.5 (26.0-39.8) | 30.7 (22.2-38.1) |
| 6 | 41.0 (31.1-47.3) | 18.9 (15.7-21.7) | 41.0 (35.9-45.1) | 21.3 (17.3-25.8) | 29.4 (23.0-32.8) | 19.7 (16.8-26.8) |
| 8 | 45.2 (42.5-50.6) | 27.6 (24.8-30.0) | 45.0 (41.6-51.0) | 31.8 (28.8-37.8) | 35.9 (26.0-43.5) | 31.2 (16.0-38.7) |
| 9 | 38.8 (34.5-43.9) | 11.5 (7.9-14.0) | 38.9 (34.8-44.0) | 11.6 (8.1-13.7) | 40.1 (34.2-47.3) | 11.4 (9.2-13.5) |
| Mean | 37.7 (24.1–50.6) | 18.6 (7.9–30.5) | 38.5 (22.6–51.0) | 21.5 (8.1–39.4) | 32.3 (20.9–47.3) | 19.9 (7.7–38.7) |
States 3,7,10 did not provide test breakdown information; serologic positivity was a two-tier IgM or IgG test, where the first tier was an enzyme immunoassay (EIA) or immunofluorescent assay (IFA), followed by a reflex immunoblot. Although not recommended to aid in patient diagnosis, a single IgG immunoblot was also sufficient laboratory evidence for surveillance purposes. A confirmed case of LD in already high-incidence areas was laboratory evidence of infection accompanied by at least one defined clinical manifestation. A probable case was any other case of clinician- diagnosed LD with laboratory evidence of infection. Two-tier data include persons positive for both IgM and IgG.