What is the role of lab tests in the workup of alcohol toxicity?

Updated: Jan 05, 2021
  • Author: Michael D Levine, MD; Chief Editor: Jeter (Jay) Pritchard Taylor, III, MD  more...
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Following consumption of any type of alcohol, the extent of the workup depends partly on the history. However, because the patient's sensorium is likely to be altered and a history unobtainable or inaccurate, a thorough physical examination is important to evaluate for occult injuries; laboratory clues can also become invaluable.

If the possibility of a suicide attempt is raised, an electrocardiogram and basic toxicology screen, including measurement of salicylate and acetaminophen concentrations, become important.

In addition, if ingestion of a toxic alcohol is suspected, a serum ethanol level and basic electrolytes, including a serum bicarbonate level are vital, as the latter are needed to calculate an anion gap. In such a situation, specific serum toxic alcohol levels immensely help guide management. If these are unavailable, calculation of an osmolar gap can sometimes be helpful, though its exclusive use is fraught with pitfalls. [21] These issues are best discussed with the local poison control center. Arterial blood gases and other tests that measure associated organ dysfunction also become important in cases of poisoning with toxic alcohols.

An important point is that laboratory abnormalities vary dramatically over the course of the patient's presentation and any laboratory abnormalities must be interpreted with the time frame of the patient's presentation in mind. Failing to do so is a common and important pitfall. Thus, early in the course of intoxication with a toxic alcohol, a patient will have neither an anion gap nor an osmolar gap though their serum toxic alcohol level will be highest shortly after ingestion. However, as metabolism of the toxic alcohol occurs, the anion and osmolar gaps develop as metabolites are formed and the toxic alcohol level drops. [22]

Other laboratory abnormalities also develop as end-organ damage occurs. Coingestion of alcohol delays all the laboratory value changes as well as the signs and symptoms of toxic alcohol-induced injury.

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