UNITS AND ABBREVIATIONS

Use only standard abbreviations. Consult the following sources for standard abbreviations: Scientific Style and Format and Standard for Use of the International System of Units (SI): the Modern Metric System (American Society for Testing and Materials. IEEE/ASTM SI 10-1997. West Conshohocken, PA: ASTM, 1997) or www.ieee.org/web/publications/PSPB/index.html. Avoid abbreviations in the title, and avoid the use of abbreviations for single words. The complete phrase or expression should precede the first use of an abbreviation in the text unless it is a standard unit of measurement, chemical compound preceded by a digit, or one of the following standard abbreviations: ADP, AIDS, AMP, ATP, DMEM, DNA, EDTA, eg, EGTA, GDP, GTP, HCl, HDL, HEPES, HIV, HPLC, ie, LDL, ln, MEM, MOPS, NAD, NADH, NADP, NADPH, RNA, RPMI, tris, and VLDL.

Abbreviations for statistical terms
coefficient of correlation, sample, r
coefficient of multiple correlation, R
coefficient of variation, CV
confidence interval, CI
degrees of freedom, df
mean,
not significant, NS
number of observations, n
probability, P
standard deviation, SD
standard error of the estimate, SEE
standard error of the mean, SEM
variance ratio, F

Metric units are required and the use of the International System of Units (SI units) is optional. For a comprehensive listing of SI conversion factors, consult SI Units for Clinical Measurement (Young DS, Huth EJ. Philadelphia: American College of Physicians, 1998) or Am J Clin Nutr 1998;67:166–81 or J Nutr 1990;120:20–35. Dosage forms and dietary ingredients may be expressed in gram or mole quantities. Energy may be expressed in kilocalories or joules; the conversion factor for converting kilocalories to kilojoules is 4.184. Do not report energy in Calories with a capital C; use kcal, MJ, or kJ instead. Temperatures should be reported in degrees Celsius. Blood pressures should be reported in millimeters of mercury. Use of katals to report enzyme activity is optional.

Commonly used approved abbreviations

Standard units of measurement		Combining prefixes
ampere, A	liter, L	tera- (1012), T	micro- (10–6), µ
becquerel, Bq	meter, m	giga- (109), G	nano- (10–9), n
coulomb, C	minute, min	mega- (106), M	pico- (10–12), p
curie, Ci	mole, mol	kilo- (103), k	femto- (10–15), f
day, d	month, mo	milli- (10–3), m	atto- (10–18), a
degree Celsius, °C	ohm, Ω
farad, F	pascal, Pa
gram, g	second, s
hertz, Hz	sievert, Sv
hour, h	volt, V
joule, J	watt, W
katal, kat	week, wk
kelvin, K	year, y
kilocalorie, kcal

Acceptable standard units	Unacceptable units
length: m, mm, µm	length: not acceptable: in, ft, yd, Å, mµ
area: m2, mm2, µm2	length: not acceptable: sq in, in2, µ2
volume: L, mL, µL, pL	volume: not acceptable: pint, gallon, cc, ccm, , µµL
mass: kg, g, mg, µg, ng, pg	mass: not acceptable: oz, lb, gr, gm, gms, mgm, mgms, mgs
mass concentration: kg/L, g/L, mg/L, µg/L	mass concentration: not acceptable: mg %
substance concentration: mol/L, mmol/L, µmol/L, nmol/L	substance concentration: not acceptable: M, N

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