Table 2 Impact of repeated sample collection on test performance.

From: Impact of repeated nasal sampling on detection and quantification of SARS-CoV-2

  MT2 positive MT2 negative MT2 indeterminate Total
a. Concordance between paired MT rRT-PCR samples (N = 74)
MT1 positive 72 0 0 72
MT1 negative 0 2 0 2
MT1 indeterminate 0 0 0 0
Total 72 2 0 74
b. Concordance between paired MT antigen samples (N = 147)
MT1 positive 39 2 0 41
MT1 negative 1 104 0 105
MT1 indeterminate 1 0 0 1
Total 41 106 0 147
  NP rRT-PCR positive NP rRT-PCR negative Total  
c. Concordance between paired MT antigen samples and NP rRT-PCR (N = 143a)  
MT1 + MT2 antigen positive 37 2 39  
MT1 + MT2 antigen negative 14 90 104  
Total 51 92 143  
  1. a: McNemar’s test for agreement of positive/negative results: N/A No discordant pairs.
  2. a: Kappa coefficient (exact 95% CI): 1.00 (N/A).
  3. a: Overall agreement (exact 95% CI): 100% (N/A).
  4. b: McNemar’s test for agreement of positive/negative results: p = 0.56.
  5. b: Kappa coefficient (exact 95% CI): 0.95 (0.88–1.00).
  6. b: Overall agreement (exact 95% CI): 97% (0.93–0.99).
  7. c: Sensitivity (exact 95% CI): 0.73 (0.58–0.84); Specificity (exact 95% CI): 0.98 (0.92–1.00).
  8. c: McNemar’s test for agreement of positive/negative results: p = 0.003.
  9. c: Kappa coefficient (exact 95% CI): 0.74 (0.63–0.86).
  10. c: Overall agreement (exact 95% CI): 88.8% (0.82–0.93).
  11. aDiscordant MT1 and MT2 antigen results excluded (n = 4).