Is the measurement of serum formate concentration useful in the diagnostics of acute methanol poisoning? A prospective study of 38 patients

Basic Clin Pharmacol Toxicol. 2015 May;116(5):445-51. doi: 10.1111/bcpt.12338. Epub 2014 Nov 18.


The aim of this article was to study the role of serum formate (S-formate) in diagnosing methanol poisoning. A prospective study was undertaken of 38 patients from the Czech methanol mass poisoning in 2012 - median age 51 [interquartile range (IQR) 37-62] years with confirmed methanol poisoning. S-formate was measured enzymatically. The receiver operating characteristics (ROC) curve was used to examine the predictive ability of S-formate. Asymptomatic patients had median S-formate of 1.9 (IQR 1.5-2.4) mmol/L. The median S-formate was 15.2 (IQR 13.9-17.6) mmol/L in symptomatic subjects with visual disturbances, 15.4 (12.1-18.0) mmol/L in subjects with dyspnoea and 15.7 (IQR 12.8-18.5) mmol/L in comatose patients. The differences in serum formate concentrations in symptomatic patients depending on clinical features were not significant (all p > 0.05). Patients with long-term visual sequelae of poisoning had median S-formate of 16.1 (IQR 14.3-19.9) mmol/L; with central nervous system (CNS) sequelae, patients had 15.9 (IQR 14.2-19.5) mmol/L. In lethal cases, the median S-formate was 15.2 (IQR 13.8-15.9) mmol/L. The probability of a poor outcome (death or survival with sequelae) was higher than 90% in patients with S-formate ≥17.5 mmol/L, S-lactate ≥7.0 mmol/L and/or pH <6.87. The ROC analysis showed that the corresponding areas under the curve (AUC) were 0.64 (0.44-0.85 CI 95%) for S-formate, 0.75 (0.56-0.93 CI 95%) for 'S-formate+S-lactate' and only 0.54 (0.38-0.69 CI 95%) for serum methanol, which is lower than for S-formate (p < 0.05). The measurement of S-formate is an important tool in the laboratory diagnostics and clinical management of acute methanol poisoning. S-formate ≥3.7 mmol/L can lead to the first clinical signs of visual toxicity, indicating haemodialysis. S-formate ≥11-12 mmol/L is associated with visual/CNS sequelae and a lethal outcome.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Adult
  • Area Under Curve
  • Biomarkers / blood
  • Czech Republic / epidemiology
  • Female
  • Formates / blood*
  • Humans
  • Hydrogen-Ion Concentration
  • Lactic Acid / blood
  • Male
  • Methanol / poisoning*
  • Middle Aged
  • Poisoning / blood*
  • Poisoning / diagnosis*
  • Poisoning / mortality
  • Poisoning / therapy
  • Predictive Value of Tests
  • Prognosis
  • ROC Curve
  • Severity of Illness Index


  • Biomarkers
  • Formates
  • formic acid
  • Lactic Acid
  • Methanol