Thanks to Dr’s Strayer and Desai for inspiring today’s pearl:
We are generally comfortable with the serum alcohol levels reported by the Sinai/EHC labs, but how does this compare to the legal limits you hear about (0.08, etc), breathalyzer tests, or the measurments used in other countries?
Blood alcohol concentration (BAC) is measured as a mass of alcohol per volume (US/Canada) or per mass of blood (some European countries). In the US and Canada alcohol concentration is reported as either mg/dL (the units we are familiar with), or as 1 percent weight/volume – equivalent to 1g per 100 ml. The latter is used in legal/lay circles.
So…to convert from legal limit in NY of 0.08 to ED measurements, just move the decimal point over by 3. Thus, 0.08 g/dL = 80 mg/dL – an “alcohol level” of 80 and over is considered DUI in NYS (for commercial drivers or <age 21 the limit i’s 40).
So, now for some ethics talk: they bring in this MVC, you dutifully check the EtOH level box; and the level is 120. Do you have a legal/ethical obligation to report him to the police for drunk driving?
Legal issues first: it varies by state (figure below). New York State does not require reporting of drunk drivers.
Ethically, given the complicated legal questions around it, the AMA has not taken an official stand on the issue, instead encouraging state medical societies to issue reccomendations to their members based on the legal framework in their respective states. The Medical Society of NY (MSSNY) also seems reluctant to take a hard stand on the issue given nonexistent legal framework in the state laws on this topic, so it has this somewhat vague recommendation:
“Physicians should educate and counsel patients, and where appropriate, their families, on the conditions compromising driving ability. Informed patients should be morally responsible for continued driving against medical advice. For drivers at marked risk for an MVA, and who persist driving despite counseling, physicians should be ethically obligated to notify DMV, so long as this disclosure results in meaningful action by the authorities. This disclosure, if made in good faith, and after substantial patient counseling, should be immune from legal liability.”
PS. Breathalyzer tests use a different measurement concentration which I won’t cover here, but be aware that breathalyzers can give false positive readings when there is “interference” from other compounds such as acetone, methanol or certain solvents. So keep that in mind when cops bring in an “etoh intox” diagnosed by breathalyzer and always correlate with a serum etoh (generally, the breathalyzers underestimate etoh levels).
Update 1/31/13: Thanks to Dr. Genes for pointing this out. Hospitals measure serum alcohol levels while forensic labs (legally the ‘gold standard’) measure whole blood concentrations. Serum alcohol levels will generally be about 15% higher than whole blood levels. Use that in mind when deciding if you need to report a suspected DUI.
From Aschkenasy MT, et al. Physician reporting of medically impaired drivers. J Emerg Med. 2006;30:29–39
Berger JT, et al. Reporting by Physicians of Impaired Drivers and Potentially Impaired Drivers. J Gen Intern Med. 2000;9:667–672.
Currier GW, et al. Innovations: Emergency psychiatry: Relative accuracy of breath and serum alcohol readings in the psychiatric emergency service. Psychiatr Serv. 2006;57:34-6.
Rainey PM. Relation between serum and whole-blood ethanol concentrations. Clin Chem. 1993;39: 2288-92.