A common contaminant of illegal alcohol products and many fluids which can be ingested by accident or in cases of self poisoning. PLEASE CONTACT THE DUTY BIOCHEMIST BEFORE SENDING SAMPLES (Ext: 26922 or Bleep 2607 between 9am and 5pm, out of hours please contact Consultant on call via switchboard). Sample type required: fluoride oxalate whole blood.
Tube
07 (FP) – Fluoride Oxalate Plasma
ID
Tests&Tubes0215
Additional Information
Methanol is directly toxic due to its suppressive effect on the central nervous system. Methanol is metabolised by alcohol dehydrogenase to formaldehyde, and then by aldehyde dehydrogenase to formic acid. Methanol poisoning can cause visual disturbance, and as little as 4 mL methanol has been reported to cause blindness. However the usual dose reported to cause ocular toxicity in an adult is 30 mL, with 60 mL the usual minimum fatal dose. Symptoms of visual disturbance may be delayed by up to 24h. Formic acid can cause a profound metabolic acidosis. Therapy for methanol poisoning is aimed at blocking the action of alcohol dehydrogenase by administration of ethanol, which is the preferred substrate, or Fomepizole, a competitive inhibitor of the enzyme. Dialysis may also be required to remove methanol and its metabolites and to provide renal support. Morbidity and mortality do not correlate directly with initial methanol concentrations; patient outcomes are significantly better for patients who are treated promptly. Samples for Methanol measurement should be collected before treatment is started and treatment should not be delayed pending a result. Severe clinical effects are associated with concentrations > 500 mg/L although formate concentrations may be a better indicator of potential toxicity than methanol concentrations alone. Symptoms are as follows: 30 to 120 mins post ingestion – clinical effects resemble those of mild ethanol inebriation with drowsiness, confusion and irritability. After a latent phase of between 6 and 30 hours symptoms include dizziness, drowsiness, vomiting, severe abdominal pain and diarrhoea. In severe cases a marked anion gap acidosis will be present and tachypnoea is common as result. Coma and convulsions may also occur. Treatment requires nasogastric aspiration or gastric lavage.
Turn around
For urgent samples: within 2 hours from arrival of sample at Birmingham City Hospital for samples received during routine hours.
Send to
Blood Sciences Cross Site
If urgent, test referred direct to Birmingham City Hospital Toxicology laboratory
Collection Con
Minimum volume: 0.5 mL
Fluoride oxalate sample preferred, EDTA sample also accepted.
Instructions to lab: DO NOT CENTRIFUGE. Discuss request with Duty Biochemist or on-call consultant. If required, send to Birmingham City Hospital toxicology lab. Ensure QR code is affixed to sample if it will arrive OOH.
Sample REQ
Blood