Table 2.
Differential diagnosis according to arterial pH, anion gap, osmol gap, and ketone bodies. For contribution to osmol gap, toxin concentration is expressed in mg/dL. The values of anion and osmol gap are influenced by the delay from exposure. *Estimation of contribution of propylene glycol (PG) concentration to osmol gap in patients receiving lorazepam infusions: [PG] mg/dL = 14.22 + 1.94*osmol gap [Ref 2]. (
Adapted from https://www.healthcare.uiowa.edu/path_handbook/Appendix/Chem/OSMO_GAP.html, accessed Dec 12, 2021)
| Arterial pH | Anion gap | Ketone | Osmol gap | Contribution to osmol gap | |
|---|---|---|---|---|---|
| Ethanol | Nl | Nl | Nl | ↑ | [Ethanol]/3.8 |
| Methanol | ↓ | ↑ | Nl | ↑ or Nl | [Methanol]/3.2 |
| Ethylene glycol | ↓ | ↑ | Nl | ↑ or Nl | [Ethylene glycol]/6.2 |
| Isopropanol | Nl | Nl | ↑ | ↑ | [Isopropanol]/6.0 |
| Propylene glycol | ↓ | ↑ | Nl | ↑ or Nl | [Propylene glycol]/2.8* |
| Alcoholic ketoacidosis | ↓ | ↑ | ↑ | ↑ | Contribution of acetone debated [3] |