Test performance of antibodies immobilized in SPR system in identification of bacteria in ulcer secretions, compared to culture results, were calculated using the following formulas:\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \mathrm{Negative}\ \mathrm{P}\mathrm{redictive}\ \mathrm{value}\ \left(\mathrm{N}\mathrm{P}\mathrm{V}\right)=\frac{\mathrm{Number}\ \mathrm{of}\ \mathrm{true}\ \mathrm{negatives}}{\left(\mathrm{N}\mathrm{umber}\ \mathrm{of}\ \mathrm{true}\ \mathrm{negatives}\right) + \left(\mathrm{N}\mathrm{umber}\ \mathrm{of}\ \mathrm{false}\ \mathrm{negatives}\right)} $$\end{document}NegativePredictivevalueNPV=NumberoftruenegativesNumberoftruenegatives+Numberoffalsenegatives\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \mathrm{Positive}\ \mathrm{P}\mathrm{redictive}\ \mathrm{value}\ \left(\mathrm{P}\mathrm{P}\mathrm{V}\right) = \frac{\mathrm{Number}\ \mathrm{of}\ \mathrm{true}\ \mathrm{positives}}{\left(\mathrm{Number}\ \mathrm{of}\ \mathrm{true}\ \mathrm{positives}\right) + \left(\mathrm{Number}\ \mathrm{of}\ \mathrm{false}\ \mathrm{positives}\right)} $$\end{document}PositivePredictivevaluePPV=NumberoftruepositivesNumberoftruepositives+Numberoffalsepositives\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \mathrm{Specificity} = \frac{\mathrm{Number}\ \mathrm{of}\ \mathrm{true}\ \mathrm{negatives}}{\left(\mathrm{Number}\ \mathrm{of}\ \mathrm{true}\ \mathrm{negatives}\right) + \left(\mathrm{Number}\ \mathrm{of}\ \mathrm{false}\ \mathrm{positives}\right)} $$\end{document}Specificity=NumberoftruenegativesNumberoftruenegatives+Numberoffalsepositives\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \mathrm{Sensitivity} = \frac{\mathrm{Number}\ \mathrm{of}\ \mathrm{true}\ \mathrm{positives}}{\mathrm{Number}\ \mathrm{of}\ \mathrm{true}\ \mathrm{positives} + \left(\mathrm{Number}\ \mathrm{of}\ \mathrm{false}\ \mathrm{negatives}\right)} $$\end{document}Sensitivity=NumberoftruepositivesNumberoftruepositives+Numberoffalsenegatives