Table 4– The relationship between the number of volatile organic compounds (VOCs) in the support vector machine model and the prediction of exacerbations: intersubject comparison
VOCs nSensitivity %Specificity %Correct classification %
9799588
8719585
77910091
66410085
57110088
46410085
34310076
23610073
12110067
  • An optimal model contained seven VOCs and had a sensitivity of 79%, a specificity of 100%, a positive predicted value of 100% and a negative predicted value of 86% (bold).