TABLE 2.
Comparison of recombinant LigB-based immunoblot assay with standard diagnostic tests for leptospirosis
| Phase of illness and time period after onset | No. of samples tested | Results for standard diagnostic evaluation
|
rLigB immunoblot (no. of positive reactions [%]) for:
|
|||
|---|---|---|---|---|---|---|
| Median maximum reciprocal MAT titer (range) | No. of samples with reciprocal MAT titer of ≥100 (%) | IgM ELISA (no. of positive reactions [%]) | IgM | IgG | ||
| Acute phase (n = 95)a | ||||||
| 2 to 6 days | 21 | 0 (0-3,200) | 7 (33) | 11 (52) | 17 (81) | 13 (62) |
| 7 to 11 days | 55 | 400 (0-6,400) | 35 (64) | 47 (85) | 52 (94) | 51 (93) |
| 12 to 23 days | 19 | 800 (0-6,400) | 15 (79) | 14 (74) | 18 (95) | 17 (89) |
| Early convalescent phase (n = 95)a | ||||||
| 18 to 28 days | 42 | 3,200 (800-25,600) | 42 (100) | 41 (98) | 37 (88) | 40 (95) |
| 29 to 36 days | 33 | 1,600 (400-12,800) | 33 (100) | 32 (97) | 25 (76) | 33 (100) |
| 37 to 113 days | 20 | 1,600 (200-6,400) | 20 (100) | 20 (100) | 7 (35) | 20 (100) |
| Late convalescent phase (n = 58)b | ||||||
| 4 to 23 mos | 24 | 400 (0-800) | 20 (83) | 23 (96) | 4 (17) | 13 (54) |
| 24 to 47 mos | 17 | 400 (100-1,600) | 17 (100) | 7 (41) | 1 (6) | 3 (18) |
| 48 to 72 mos | 17 | 200 (200-800) | 15 (88) | 5 (29) | 1 (6) | 3 (18) |
a
Paired samples were obtained from 95 leptospirosis cases (n) in Salvador, Brazil. Early-convalescent-phase samples were obtained more than 14 days and less than 4 months after collection of acute-phase samples.
b
Late-convalescent-phase samples were obtained from leptospirosis patients 4 months to 72 months after discharge from hospital.