I can state from experience that a leading decimal point can be harmful
of even fatal in healthcare. But, there is a general decimal illiteracy
in US society, one that affects doctors and nurses. In fact, as I
mentioned on this list in the recent past, a co-worker of mine, in
pharmacy, could not easily convert grams to milligrams and vice versa.
The decimal illiteracy usually shows up in the dosing of levothyroxine,
a thyroid hormone supplement, which is often ordered in both milligram
and microgram doses. Often, the dose 0.025 mg gets mis-transcribed as
0.25 mg, or the drug is ordered as 250 milligrams instead of 250
micrograms. Despite being the innovators in decimalizing currency, we
Americans have a clear lack of facility in thinking decimally.
But, I think I was lucky in attending the Boston Public Schools when I
did (1956-64). We received an extensive arithmetical education, both in
decimal numeration and in the use of expressed fractions (i.e., the
WOMBAT system of numeration). I don't know if schools are as tough today
as they were then, but my elementary-school contemporaries were made to
run the mathematical gauntlet of the times.
Another poor prescription writing practice is the use of a trailing zero
when it is not a significant digit. If the decimal point is not clearly
legible, and there is a ten-fold strength of the drug available, 2.0 mg
can become 20 mg. There is NO reason to write "2.0 mg"!!! "2 mg" is all
that is required.
A few (VERY few) prescribers write ALL of their prescriptions in grams,
i.e., if there is a 1 mg dose, the order is written as 0|001, and 25 mcg
is written as 0|000|025. This would be a good safeguard if everybody did
it as a standard notation, but few do it, and it probably raises more
questions than it answers when it appears.
The best solution to this communication problem is mathematical facility
in using decimals and in using SI, so the writer writes either 0.025 mg
OR 25 mcg (sorry, I don't have a "mu" handy) and the reader can
understand either notation.
I must also confess that use of the SI "mu" prefix for "micro" can cause
confusion in medication orders, since a careless writer will make the
"mu" look like "m", so we have to read between the lines and/or call the
prescriber to verify (time for electronic order entry in all medication
orders!).
--
Paul Trusten, R.Ph.
3609 Caldera Boulevard, Apt. 122
Midland TX 79707-2872 USA
[EMAIL PROTECTED]
