Table 4.
Tentative Identification of VOC Biomarkers of Influenza Infection
| VOC Number | AUC | Fit | VOC Identification |
|---|---|---|---|
| 1 | 0.75 | 879 | (R)-(-)-2-Amino-1-Propanol |
| … | … | 859 | Hydroxyurea |
| … | … | 848 | Topotecan |
| 2 | 0.74 | 725 | 2-Butanamine, N-Nitro- |
| … | … | 701 | 1-Propanamine, N, 2-Dimethyl-N-Nitro- |
| … | … | 650 | Isothiourea, 2-(2-Octylsulfonyl)Ethyl- |
| 3 | 0.73 | 747 | Hexanal, 3-Methyl- |
| … | … | 669 | Butane, 1-(Ethenyloxy)-3-Methyl |
| … | … | 643 | Pentane, 1-(Ethenyloxy)- |
| 4 | 0.73 | 973 | Heptane |
| … | … | 948 | Hexane, 3-Methyl- |
| … | … | 906 | Pentane, 2,3-Dimethyl- |
| 5 | 0.73 | 917 | (1R)-26,6-Trimethylbicyclo[3.1.1]Hept-2 |
| … | … | 907 | Alpha-Pinene |
| … | … | 901 | Trans-Beta-Ocimene |
The list displays the 5 major breath biomarkers of influenza infection, each with its top 3 tentative identifications. AUC indicates a biomarker's accuracy when it was employed alone. “Fit” is a numerical value assigned by the NIST computer-based library as an indicator of “goodness of fit” of the mass spectrum of a breath VOC compared with similar mass spectra in the library. Fit values range from 0 (no fit) to 1000 (perfect fit). Values >700 or >800 are generally considered “good” to “very good” fits. However, these identifications may only be considered tentative. A number of the tentative VOC identifications comprised either straight-chain n-alkane hydrocarbons (eg, heptane) or their methylated derivatives (eg, hexane-3-methyl). These VOCs are all consistent with products of oxidative stress. Abbreviations: AUC, area under the curve; NIST, National Institute of Standards and Technology; VOC, volatile organic compound.