Rapid Test for Ethylene Glycol Poisoning

Ethylene glycol poisoning is often suspected when an anion gap and osmolar gap are both present in a patient with alcohol dependence or ingestion. But confirmation of the diagnosis, desirable because treatment is expensive and not without risk, usually requires sending a blood sample to an outside laboratory and waiting for results. In a prospective observational study, researchers employed a rapid qualitative test already in use by veterinarians to test for ethylene glycol in 24 blood samples from human subjects with suspected toxic alcohol poisoning. Gas chromatography was the reference standard.

• The qualitative test detected ethylene glycol in all 15 samples that were positive for ethylene glycol by gas chromatography (sensitivity, 100%).

• The qualitative test was negative in 5 samples that tested positive for methanol but not ethylene glycol.

• One of 4 samples negative for methanol and ethylene glycol by gas chromatography tested positive by the qualitative test (specificity, 89%).

Comments:

Clearly, a larger study regarding this test’s operating characteristics is needed before it can be recommended for widespread use in humans. I suspect the sensitivity and specificity will not be as good. But the results look promising, and having a rapid test would be a great help to clinicians who currently have to decide whether to institute treatment with fomepizole, ethanol, or hemodialysis based on nonspecific clinical findings.

Richard Saitz, MD, MPH

Reference:

Long H, Nelson LS, Hoffman RS. A rapid qualitative test for suspected ethylene glycol poisoning. Acad Emerg Med. 2008;15(7):688–690.