Volume 25, Number 10—October 2019
Research
Sensitive and Specific Detection of Low-Level Antibody Responses in Mild Middle East Respiratory Syndrome Coronavirus Infections
Table 3
Sensitivity and specificity results of routinely used commercial S1 ELISA and PRNT90 assays for MERS-CoV*
Assay parameter and sample source | Infection | No. positive/no. tested |
|||||
---|---|---|---|---|---|---|---|
S1 rELISA† | PRNT90 (titer) |
Specificity or sensitivity, % |
|||||
S1-positive | S1-negative | S1 rELISA | PRNT90 | ||||
Specificity | 98.97 | 93.33 (1:20); 99.5 (1:40) | |||||
Healthy blood donors | None | 0/50 | NA | 0/50 | |||
Non-CoV respiratory infections | Adenovirus | 0/5 | NA | 1/5(20) | |||
Bocavirus | 0/2 | NA | 0/2 | ||||
Enterovirus | 0/2 | NA | 0/2 | ||||
HMPV | 0/9 | NA | 1/9 (20) | ||||
Influenza A | 0/13 | NA | 4/13 (20, 20, 20, 20) | ||||
Influenza B | 0/6 | NA | 0/6 | ||||
Rhinovirus | 0/9 | NA | 2/9 (20, 20) | ||||
RSV | 0/9 | NA | 1/9 (20) | ||||
PIV-1 | 0/4 | NA | 0/4 | ||||
PIV-3 | 0/4 | NA | 0/4 | ||||
Mycoplasma | 0/1 | NA | 0/1 | ||||
CMV | 0/9 | NA | 0/9 | ||||
EBV | 0/12 | NA | 0/12 | ||||
Recent CoV infections‡ | α-CoV HCoV-229E | 0/19 | NA | 3/19 (20, 20, 20) | |||
α-CoV HCoV-NL63 | 0/18 | NA | 0/18 | ||||
β-CoV HCoV-OC43 |
2/23 |
0/2 |
1/21 (80) |
||||
Sensitivity | |||||||
Persons with camel contact | S1-microarray positive§ | 4/19 | 4/4 (40, 40, 40, 20) | 6/15 (40, 40, 20, 20, 20, 20) | 21 | 52.6 | |
S1-microarray negative | 0/18 | NA | 1/18 (20) | NA | NA | ||
RT-PCR–confirmed MERS cases | <14 d postdiagnosis | 11/21 | 11/11 | 1/10 (80) | NA | NA | |
>14 d postdiagnosis | 7/7 | 7/7 | NA | 100 | 100 | ||
6–12 mo postdiagnosis; mild infection | 5/17 | 5/5 | NA | 35.3 | 35.3 | ||
6–12 mo postdiagnosis; severe infection | 15/15 | 15/15 | NA | 100 | 100 |
*CMV, cytomegalovirus; CoV, coronavirus; EBV, Epstein-Barr virus; ELISA, enzyme-linked immunosorbent assay; HCoV, human coronavirus; HMPV, human metapneumovirus; MERS, Middle East respiratory syndrome; NA, not applicable; PIV, parainfluenza virus; PRNT, plaque reduction neutralization test; PRNT90, 90% endpoint PRNT; rELISA, routine ELISA; RSV, respiratory syncytial virus; RT-PCR, reverse transcription PCR.
†None of the serum samples from specificity cohorts tested positive by in-house S1 ELISA or microarray.
‡Cross-reactivity.
§All 19 serum samples (protein microarray positive) tested positive by in-house S1 ELISA.