Table 2.
List of different classes of outliers and their related atypical deviations
| Type of class | Outlier class | Mmol/mol Crea | Number of outliers | Ppm region | |
|---|---|---|---|---|---|
| Ketosis | 2 | >1,000 | 7 | 2.25–2.45 and 1.18–1.23 | |
| Medication | 3 | \ | 15 | 7.39–7.59 | |
| Panthenol gel | 4 | >100 | 1 | 0.85–0.96 | |
| High concentration of known metabolite | Succinic acid | 5 | >800 | 4 | 2.4–2.42 |
| Acetic acid | 6 | >4,000 | 3 | 1.91–1.94 | |
| Lactic acid | 7 | >1,300 | 3 | 1.31–1.355 | |
| 4-Hydroxyphenyllactic acid | 8 | >900 | 4 | 6.84–6.88 and 7.16–7.20 | |
| 4-Hydroxyphenylacetic acid | 9 | >150 | 2 | 7.15–7.18 | |
| Acetoacetic acid | 10 | >400 | 1 | 2.27–2.29 | |
| Myo-inositol | 11 | >5,000 | 9 | 3.27–3.3 | |
| N,N-Dimethylglycine | 12 | >850 | 1 | 2.92–2.94 | |
| d-Lactose | 13 | >2,000 | 5 | 4.45–4.48 | |
| d-Glucose | 14 | >4,000 | 6 | 4.63–4.67 | |
| Sucrose | 15 | >950 | 1 | 4.2–4.3 | |
| Tiglyglycine | 16 | >800 | 1 | 6.45–6.55 and 1.75–1.85 | |
| N-Phenylacetylglycine | 17 | >50 | 1 | 7.8–7.85 | |
| Salicylurate | 18 | >250 | 1 | 7–7.05 | |
| Threonate | 19 | >1,200 | 1 | 4–4.2 | |
| Gluconate | 20 | >4,500 | 1 | 3.7–4.1 | |
| Propylene glycol | 21 | >700 | 3 | 1.1–1.18 and 3.4–3.6 and 3.85–3.9 | |
| Ethanol | 22 | >11,000 | 1 | 1.18–1.21 | |
| Mannitol | 23 | >1,000 | 1 | 3.6–4 | |
| Proline | 24 | >2,000 | 1 | 1.95–2.1 | |
| Proteinuria | 25 | – | 8 | 0.5–2.5 | |
| Jaundice | 26 | – | 4 | 7.5–7.7 | |
| Unknown signal | Single signal | 28 | 19 | ||
| Multiple signals | 29 | 69 | |||
| Unknown sugars | 30 | 4 | 3–4.5 | ||
The number of outliers refers to the INFAI data set. In about half of the outliers related a-typical signals are not yet identified