Table 3. Interlaboratory geometric coefficients of variation of absolute titers and titers and relative to candidate antibody standard 07/150 and sheep serum summarized over all serum for each influenza virus tested by hHI and neutralization*.
| %GCV, virus strain | hHI, all serum samples, median (min–max) | Neutralization, all serum samples, median (min–max) |
|---|---|---|
| %GCV of absolute titer | ||
| A/Vietnam/1194/NIBRG-14 clade 1 | 125 (31–582)† | 175 (86–232)† |
| A/Turkey/23/NIBRG-23 clade 2.2 | 114 (29–496) | 170 (101–283) |
| A/Anhui/IBCDC-RG5 clade 2.3 |
108 (22–487) |
112 (68–147) |
| %GCV of titers relative to 07/150 | ||
| A/Vietnam/1194/NIBRG-14 clade 1 | 61 (34–535) | 77 (37–285) |
| A/Turkey/23/NIBRG-23 clade 2.2 | 106 (18–487) | 144 (33–309) |
| A/Anhui/IBCDC-RG5 clade 2.3 |
105 (0–545) |
196 (41–298) |
| %GCV of titers relative to serum P | ||
| A/Vietnam/1194/NIBRG-14 clade 1 | 796 (39–1,020) | 249 (162–381) |
| A/Turkey/23/NIBRG-23 clade 2.2 | 689 (7–953) | 237 (90–844) |
| A/Anhui/IBCDC-RG5 clade 2.3 | 752 (0–1,005) | 195 (66–263) |
| A/Vietnam/1194/NIBRG-14 clade 1 (excluding laboratory 5) | 68 (32–174) | 255 (162–396) |
| A/Turkey/23/NIBRG-23 clade 2.2 (excluding laboratory 5) | 70 (7–222) | 237 (90–844) |
| A/Anhui/IBCDC-RG5 clade 2.3 (excluding laboratory 5) |
51 (0–148) |
195 (66–262) |
| %GCV of titers relative to serum 0 | ||
| A/Vietnam/1194/NIBRG-14 clade 1 | 442 (21–725) | 78 (41–213) |
| A/Turkey/23/NIBRG-23 clade 2.2 | 373 (20–804) | 111 (29–204) |
| A/Anhui/IBCDC-RG5 clade 2.3 | 306 (0–812) | 199 (44–323) |
| A/Vietnam/1194/NIBRG-14 clade 1 (excluding laboratories 5, 6, 12) | 39 (24–91) | 82 (34–225) |
| A/Turkey/23/NIBRG-23 clade 2.2 (excluding laboratories 5, 6, 12) | 113 (22–225) | 97 (25–186) |
| A/Anhui/IBCDC-RG5 clade 2.3 | 100 (0–198) | 194 (47–299) |
*%GCV, geometric coefficient of variation; hHI, hemagglutination-inhibition assay using horse erythrocytes; neutralization, virus neutralization assay; min–max, minimum–maximum. Boldface indicates homologous clade 1 strain. †%GCV absolute titer vs. relative 07/150 for NIBRG-14 (*hHI p = 0.001, neutralization p = 0.002; Wilcoxon signed-rank test).