Table 1 Dengue antibody detection by ELISA in serum and reconstituted filter paper blood of Vietnamese febrile patients, repeated tests and storage time of specimens.
From: Enzyme-linked immunoassay for dengue virus IgM and IgG antibodies in serum and filter paper blood
| Â | Dengue tests in febrile patients | |||
|---|---|---|---|---|
| Â | Upon presentation (t0) | After convalescence (t3) | ||
| Â | IgM | IgG | IgM | IgG |
Total cases tested | 781 | |||
Storage time (days, median, range) | 252 (57 – 751) days | 228 (36 – 730) | ||
No. positive sera (index value ≥1) | 222 (28%) | 673 (86%) | 261 (33%) | 679 (87%) |
No. cases tested twice | 73 | 74 | 73 | 73 |
Median storage time first test (days, range) | 114 (57 – 283) | 92.5 (36 – 253) | ||
Median storage time second test (days, range) | 280 (225 – 798) | 259 (204 – 777) | ||
No. positive first test | 9 (12%) | 59 (80%) | 17 (23%) | 56 (77%) |
No. positive second tests | 23 (32%) | 63 (85%) | 23 (32%) | 61 (84%) |
P value (Chi Square test) | <0.001 | <0.001 | <0.001 | <0.001 |
No. of combined sera and blood spots on filter paper tested | 161 | |||
Median storage time (days, range) | 283 (139 – 795) | 262 (118 – 774) | ||
No. positive sera | 46 (29%) | 121 (75%) | 89 (55%) | 128 (80%) |
No. positive filter papers | 8 (5%) | 97 (60%) | 55 (34%) | 123 (76%) |
P value (Chi Square test) | <0.0001 | < 0.0001 | <0.0001 | <0.0001 |
Kappa value | 0.191 | 0.391 | 0.567 | 0.549 |