Table 1. Reference values and positivity thresholds for a multiplex bead assay based on antigens from chikungunya and dengue viruses and Plasmodium falciparum.
| Pathogen, antigen | Reference samplea | Fluorescence intensityb |
|
|---|---|---|---|
| Median for study samples (range) | Threshold | ||
| Chikungunya virus | |||
| Envelope 1 antigen of mutant A226V | Blood | 101 (−9 to 30 027) | 640 |
| Dengue virus | |||
| DENV-2 virus-like particle | Sera | 10 168 (−18 to 28 395) | 982 |
| DENV-3 virus-like particle | Sera | 15 047 (3 to 30 214) | 3615 |
| Plasmodium falciparum | |||
| 19-kDa fragment of MSP-1 of clone 3D7, linked to GST | Sera | 8 (−6 to 21 627) | 105 |
| 42-kDa fragment of MSP-1 of clone 3D7 | Sera | 29 (2 to 23 913) | 189 |
| 42-kDa fragment of MSP-1 of clone FVO | Sera | 20 (0 to 20 489) | 79 |
| GSTc | Sera | 7 (−4 to 173) | NA |
GST: glutathione-S-transferase; MSP-1: merozoite surface protein 1; NA: not applicable.
a The reference samples were 86 sera from adults who claimed to have never left the United States or 156 spots of blood collected from 62 Haitian children between 2011 and 2013.
b Each reported intensity is the result of subtracting background fluorescence, from wells containing no primary antibody, from the mean of the median fluorescence intensities of duplicate wells.
c Used as a protein-negative control.