Table 2 Thin film sensitivity and other factors by parasite density and reader level
From: Pilot assessment of the sensitivity of the malaria thin film
Sensitivity | Time to 1st Parasite | Field to 1st Parasite | % Typical 1st | RBC's Field 1st Parasite | Time to 2nd Parasite | Field to 2nd Parasite | % Typical 2nd | RBC's Field 2nd Parasite | Total Parasites | Total Fields | Total Time | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Parasite | (95% CI) | |||||||||||||
Densiy | n | |||||||||||||
Expert | < 100 | 18 | 44% (19–70%) | 5.2 ± 4.3* (12)** | 133 ± 174 | 100 ± 0 | 208 ± 95 | 4.8 ± 2.5 | 189 ± 137 | 50 ± 55 | 109 ± 100 | 1.0 ± 1.8 | 523 ± 202 | 22 ± 11 |
101–200 | 20 | 55% (31–79%) | 7.2 ± 6.6 (20) | 272 ± 264 | 100 ± 0 | 217 ± 89 | 9.2 ± 3.9 | 237 ± 110 | 67 ± 52 | 158 ± 137 | 1.1 ± 1.5 | 572 ± 228 | 21 ± 7 | |
201–300 | 6 | 100% (NA) | 4.7 ± 3.6 (10) | 119 ± 83 | 98 ± 4 | 162 ± 61 | 4.2 ± 2.1 | 83 ± 67 | 100 ± 0 | 178 ± 77 | 6.2 ± 3.1 | 494 ± 239 | 26 ± 10 | |
301–500 | 6 | 100% (NA) | 2.7 ± 1.6 (5) | 61 ± 47 | 100 ± 0 | 214 ± 103 | 3.6 ± 2.8 | 56 ± 47 | 100 ± 0 | 267 ± 116 | 7.7 ± 3.4 | 560 ± 201 | 32 ± 13 | |
501–1000 | 6 | 100% (NA) | 1.3 ± 1.0 (3) | 29 ± 38 | 100 ± 0 | 186 ± 50 | 1.5 ± 0.5 | 27 ± 31 | 100 ± 0 | 195 ± 78 | 8.7 ± 3.9 | 276 ± 141 | 27 ± 11 | |
1001–2000 | 8 | 100% (NA) | 1.1 ± 1.2 (4) | 17 ± 33 | 100 ± 0 | 184 ± 101 | 2.0 ± 2.2 | 38 ± 46 | 100 ± 0 | 201 ± 113 | 10.0 ± 0.9 | 198 ± 168 | 19 ± 5 | |
>2000 | 8 | 100% (NA) | 1.4 ± 1.2 (4) | 7 ± 6 | 100 ± 0 | 157 ± 51 | 1.6 ± 1.0 | 11 ± 8 | 100 ± 0 | 183 ± 56 | 10.8 ± 1.0 | 96 ± 56 | 26 ± 5 | |
Qualified | < 100 | 27 | 37% (18–57%) | 7.6 ± 3.0 (11) | 175 ± 133 | 96 ± 7 | 185 ± 48 | 6.7 ± 7.5 | 302 ± 179 | 40 ± 55 | 98 ± 144 | 0.5 ± 0.8 | 443 ± 218 | 22 ± 10 |
101–200 | 30 | 40% (21–59%) | 9.3 ± 8.8 (30) | 123 ± 60 | 100 ± 1 | 182 ± 34 | 7.7 ± 5.1 | 294 ± 184 | 56 ± 52 | 136 ± 128 | 0.5 ± 0.7 | 376 ± 130 | 18 ± 9 | |
201–300 | 9 | 78% (44–112%) | 5.9 ± 3.5 (10) | 156 ± 141 | 99 ± 2 | 210 ± 107 | 4.3 ± 2.1 | 87 ± 34 | 99 ± 2 | 146 ± 93 | 3.9 ± 3.7 | 488 ± 245 | 24 ± 13 | |
301–500 | 9 | 89% (63–115%) | 3.0 ± 1.9 (6) | 75 ± 98 | 99 ± 2 | 254 ± 58 | 5.0 ± 3.8 | 62 ± 48 | 99 ± 2 | 247 ± 57 | 3.6 ± 3.2 | 418 ± 137 | 18 ± 9 | |
501–1000 | 9 | 100% (NA) | 6.1 ± 6.5 (20) | 39 ± 29 | 97 ± 5 | 189 ± 50 | 4.4 ± 3.5 | 37 ± 27 | 98 ± 4 | 200 ± 47 | 7.7 ± 3.9 | 403 ± 246 | 23 ± 10 | |
1001–2000 | 12 | 100% (NA) | 3.7 ± 4.1 (15) | 42 ± 41 | 98 ± 3 97 | 201 ± 62 | 5.1 ± 8.4 | 23 ± 19 | 97 ± 5 | 191 ± 46 | 8.7 ± 3.6 | 243 ± 111 | 15 ± 6 | |
>2000 | 12 | 100% (NA) | 6.0 ± 3.2 (11) | 45 ± 73 | ± 3 | 189 ± 59 | 4.3 ± 3.8 | 18 ± 18 | 98 ± 5 | 198 ± 77 | 10.2 ± 3.0 | 181 ± 81 | 25 ± 11 | |
Expert | Total | 72 | 74% (63–84%) | 4.5 ± 5.2 (15) | 120 ± 165 | 100 ± 2 | 206 ± 83 | 4.7 ± 4.4 | 96 ± 124 | 91 ± 28 | 203 ± 98 | 3.5 ± 4.2 | 495 ± 225 | 23 ± 10 |
Qualified | Total | 108 | 64% (55–73%) | 7.2 ± 5.6 (17) | 106 ± 98 | 98 ± 4 | 200 ± 61 | 5.2 ± 5.2 | 97 ± 136 | 88 ± 30 | 182 ± 87 | 2.3 ± 3.9 | 356 ± 168 | 18 ± 9 |