Serum osmolality in alcohol ingestions: differences in availability among laboratories of teaching hospital, nonteaching hospital, and commercial facilities.
Freezing point depression osmometry is preferred over vapor pressure with ingestions of volatile substances. Sixty-six laboratories nationwide (23 teaching hospital, 22 nonteaching hospital, and 21 commercial facilities) were surveyed to determine the availability and use of these techniques. Overall, 80% conducted serum osmometry (teaching, 100%; nonteaching, 82%; commercial, 57%). Freezing point depression was the most common method used by all laboratories; however, 33% of commercial laboratories and 11% of nonteaching laboratories used vapor pressure exclusively. One half of all laboratory supervisors did not identify why one method was preferred. Only 3% identified vapor pressure as a possible source of error in ingestions of volatile substances. Most laboratories estimated that they were aware of the patient diagnosis less than 50% of the time. Because vapor pressure osmometry is a potential source of false negative results when estimating serum concentrations of volatile substances, clinicians treating patients who have ingested ethanol, ethylene glycol, isopropanol, or methanol need to be aware of the methodology used in their reference laboratories.
Eisen
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TF
Division of Clinical Pharmacology/Toxicology, Children's Hospital, Harvard Medical School, Boston, MA.
Lacouture
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PG
Woolf
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A
D000438:Alcohols / Q000097:blood / Q000506:poisoning*; D006784:Hospitals, Teaching; D006801:Humans; D007753:Laboratories / Q000592:standards*; D007755:Laboratories, Hospital / Q000592:standards; D009994:Osmolar Concentration; D012494:Sampling Studies; D014481:United States; D014835:Volatilization
D000438:Alcohols