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Table 2 Calculation of the neutralizing antibody titer determined with NT-PCR assay (1.) and its intra- and inter-assay variability (2.)

From: Rapid detection of anti-Vaccinia virus neutralizing antibodies

1. Calculation of the NT-PCR assay
   Σ R2single well*
antibody dilution assay # 1a 2a 3a 4a 5a 6b 7c   
1:40 0.0250   0.25 0.31 0.27 0.33 0.22 0.32 0.31   
1:80 0.0125   1.34 1.37 1.31 1.37 1.26 1.35 1.42   
1:160 0.0063   1.44 1.36 1.28 1.27 1.30 1.23 0.71   
1:320 0.0031   1.61 1.52 1.45 1.49 1.17 1.44 1.11   
1:640 0.0016   1.20 1.77 1.65 1.73 1.41 1.65 1.43   
1:1280 0.0008   1.23 1.34 1.30 1.54 1.30 1.41 1.06   
1:2560 0.0004   1.24 1.36 1.39 1.38 1.31 1.46 1.26   
1:5120 0.0002   0.25 0.31 0.27 0.33 0.22 0.32 0.31   
2. Inter-and intra-assay precision
   respective NT-PCR titer for each assay   
   day 1 day 2 day 3 day 4 inter-assay variability
   assay 1 1:320 assay 3 1:640 assay 4 1:640 assay 5 1:640 1:640± one dilution
   assay 2 1:640         
   assay 6 1:640         
   assay 7 1:640         
intra-assay variability 1:640± one dilution         
  1. *R2 is the R-squared value (R-squared value is the fraction of the variance in the data that is explained by a regression); ΣR2 is the sum of R12 and R22; single well sample 1-7: a mean value resulting from two wells; b mean value resulting from three wells; c mean value resulting from four wells; NT-PCR antibody titer is highlighted in bold and underlined and corresponds to the highest ΣR2