Apparently there were efforts to harmonize the lab values used in the US labs with those used by the rest of the world. Never worked out. In medical school, during the first two didactic years, both the "US" and "SI" are still taught, but once medical students enter their clinical years, everything is in "US" values. Some European countries use these values as well, so this is not just our problem here.
This reminds me of one of the residents telling me why he wouldn't want to work in Canada. One of the major reasons was having to relearn all the lab values, which are SI over there. On Sun, May 19, 2013 at 6:46 PM, James Frysinger <j...@metricmethods.com>wrote: > I'm inclined to agree with what you and John Steele are saying -- that the > prefixed denominator is what causes the article's author(s) to deem the > first example non-SI. > > Of course, denominators with prefixed units are not banned in the SI, they > just are not the preferred format. > > Jim > > > On 2013-05-19 16:54, Paul Trusten wrote: > >> Jim, it is weird. Call it an American affectation. From what I can >> gather from my brief study of medical laboratory science, there is a US use >> of laboratory units that differs from those in the rest of the world. I >> think the difference lies in the perception in the US that if SI *BASE* >> units are used in expressing the concentration of the substance being >> measured, the LABORATORY units are considered to be SI, while the units >> used in the US are "not" SI. I think that if they knew what they were >> talking about, they would say "non-US," not "non-SI." Actually, I think (I >> could be wrong) that the US units are called either "US" or "standard." >> >> For example, the unit used to measure blood glucose in American labs is >> mg/dL, while outside the US, it is mmol/L. Blood glucose meters usually >> have a switch on them to allow the patient to toggle betwee mg/dL and >> mmol/L, presumably depending upon the country of usage. >> >> So, it is SI to them only if they use an SI base unit (mol) in the >> numerator of the concentration. Nyuk, nyuk, nyuk. >> It just seems to me the keepers of the medical laboratory units may need >> to brush up on how SI is applied. >> >> >> Paul Trusten, Reg. Pharmacist >> Vice President >> U.S. Metric Association, Inc. >> Midland, Texas USA >> www.metric.org >> +1(432)528-7724 >> trus...@grandecom.net >> >> >> On May 19, 2013, at 15:55, James Frysinger <j...@metricmethods.com> >> wrote: >> >> I was doing some research for my sister's use of vitamin B12 supplements >>> and came to this page: >>> >>> http://www.webmd.com/diet/**vitamin-b12-15239?page=2<http://www.webmd.com/diet/vitamin-b12-15239?page=2> >>> >>> It contains a small chart: >>> Vitamin B12Normal: >>> More than 200-835 picograms per milliliter (pg/mL) >>> 148-616 picomoles per liter (pmol/L) (SI units) >>> >>> Interestingly, WebMD apparently considers picomoles per liter to be in >>> SI units but picograms per milliliter not to be in SI units. >>> >>> Of course, the non-SI unit is the liter (or milliliter) but that's >>> acceptable for use with the SI. So, in my mind neither value statement is >>> "more SI" than the other. >>> >>> How do you view this, Paul Trusten? >>> >>> Jim >>> >>> >>> >> >> >> >> >
