Units of Measure
JAMA and the Archives Journals report quantitative values in conventional units. A number of analytes, however, are dual reported in the International System of Units (SI units, Système International d'Unités), with conventional units first, followed by the SI conversion in parentheses. See 18.5, Units of Measure, Conventional Units and SI Units in JAMA and the Archives Journals.
Use the following abbreviations and symbols with a numerical quantity in accordance with guidelines in 18.0, Units of Measure. See especially 18.5, Units of Measure, Conventional Units and SI Units in JAMA and the Archives Journals; Table 2 in chapter 18, Selected Laboratory Tests, References Ranges with and Conversion Factors; and 8.4, Punctuation, Forward Slash (Virgule, Solidus). Exception: The following example is an acceptable format in table footnotes or figure legends:
SI conversion factor: To convert creatinine value to mmol/L, multiply by 88.4.
Note: Do not capitalize abbreviated units of measure (unless the abbreviation itself is always capitalized or contains capital letters).
acre |
acre |
ampere |
A |
angstrom |
Convert to nanometers (1 angstrom = 0.1 nm). |
atmosphere, standard |
atm |
bar |
bar |
barn |
b* |
base pair |
bp* |
becquerel |
Bq |
billion electron volts |
GeV* |
Bodansky unit |
BU* |
British thermal unit |
BTU |
calorie |
cal |
candela |
cd* |
Celsius |
C (Use closed up with degree symbol, eg, 40°C.) |
centigram |
cg |
centimeter |
cm |
centimeters of water |
cm H2O |
centimorgan |
cM |
centipoise |
cP |
coulomb |
C* |
counts per minute |
cpm |
counts per second |
cps |
cubic centimeter |
cm3 (Use milliliter for liquid and gas measure.) |
cubic foot |
cu ft |
cubic inch |
cu in |
cubic meter |
m3 |
cubic micrometer |
μm3 |
cubic millimeter |
mm3 (Use microliter for liquid and gas measure.) |
cubic yard |
cu yd |
curie |
Ci |
cycles per second |
Use hertz. |
dalton |
Da |
day |
d† |
decibel |
dB |
decigram |
Convert to grams. |
deciliter |
dL |
decimeter |
Convert to meters. |
diopter |
D* |
disintegrations per minute |
dpm* |
disintegrations per second |
dps* |
dyne |
dyne |
electron volt |
eV |
electrostatic unit |
ESU* |
equivalent |
Eq |
equivalent roentgen |
equivalent roentgen |
Fahrenheit |
F (Use closed up with degree symbol, eg, 99°F.) |
farad (electric capacitance) |
F* |
femtogram |
fg |
femtoliter |
fL |
femtomole |
fmol |
fluid ounce |
fl oz |
foot |
ft (Convert to meters; query author.) |
gas volume |
gas volume |
gauss |
G |
gigabyte |
GB |
grain |
grain |
gram |
g |
gravity (acceleration due to) |
g (Use closed up to preceding number, eg, 200g.) |
gray |
Gy |
henry |
H* |
hertz |
Hz |
horsepower |
hp |
hour |
h† |
immunizing unit |
ImmU* |
inch |
in |
international benzoate unit |
IBU* |
international unit |
IU |
joule |
J |
katal |
kat* |
kelvin |
K |
kilobase |
kb* |
kilobyte |
kB |
kilocalorie |
kcal |
kilocurie |
kCi |
kilodalton |
kDa |
kiloelectron volt |
keV |
kilogram |
kg |
kilohertz |
kHz |
kilojoule |
kJ |
kilometer |
km |
kilopascal |
kPa |
kilovolt |
kV |
kilovolt-ampere |
kVA |
kilovolt (constant potential) |
kV(cp)* |
kilovolt (peak) |
kV(p)* |
kilowatt |
kW |
King-Armstrong unit |
King-Armstrong unit |
knot |
knot |
liter |
L |
lumen |
lumen |
lux |
lux |
megabyte |
MB |
megacurie |
MCi |
megacycle |
Mc |
megahertz |
MHz |
megaunit |
MU |
megawatt |
MW |
meter |
m |
metric ton |
metric ton |
microampere |
μA |
microcurie |
μCi |
microfarad |
μF* |
microgram |
μg |
microliter |
μL |
micrometer |
μm |
micromicrocurie |
Use picocurie. |
micromicrogram |
Use picogram. |
micromicrometer |
Use picometer. |
micromolar |
μM |
micromole |
μmol |
micron |
Use micrometer. |
micronormal |
μN |
microosmole |
μOsm |
microunit |
μU |
microvolt |
μV |
microwatt |
μW |
mile |
mile |
miles per hour |
mph |
milliampere |
mA |
millicurie |
mCi |
millicuries destroyed |
mCid* |
milliequivalent |
mEq |
millifarad |
mF* |
milligram |
mg |
milligram-element |
mg-el* |
milli-international unit |
mIU |
milliliter |
mL |
millimeter |
mm |
millimeters of mercury |
mm Hg |
millimeters of water |
mm H2O |
millimolar |
mM |
millimole |
mmol |
million electron volts |
MeV |
milliosmole |
mOsm |
millirem |
mrem |
milliroentgen |
mR |
millisecond |
ms† |
milliunit |
mU |
millivolt |
mV |
milliwatt |
mW |
minute (time) |
min† |
molar |
M |
mole |
mol |
month |
mo† |
morgan |
M* |
mouse unit |
MU* |
nanocurie |
nCi |
nanogram |
ng |
nanometer |
nm |
nanomolar |
nM |
nanomole |
nmol |
newton |
N |
normal (solution) |
N |
ohm |
Ω |
osmole |
osm |
ounce |
oz |
outflow (weight) |
C* |
parts per million |
ppm |
pascal |
Pa |
picocurie |
pCi |
picogram |
pg |
picometer |
pm |
picomolar |
pM |
picomole |
pmol |
pint |
pt |
pound |
lb (Convert to milligrams, kilograms, or grams; query author.) |
pounds per square inch |
psi |
prism diopter |
PD, Δ* |
quart |
qt |
rad |
rad |
radian |
radian |
rat unit |
RU* |
revolutions per minute |
rpm |
roentgen |
R |
roentgen equivalents human (or mammal) |
rem |
roentgen equivalents physical |
rep |
Saybolt seconds universal |
SSU* |
second |
s† |
siemen |
siemen |
sievert |
Sv |
sp g |
specific gravity (Use with a number, eg, sp g 13.6.) |
square centimeter |
cm2 |
square foot |
sq ft |
square inch |
sq in |
square meter |
m2 |
square millimeter |
mm2 |
Svedberg flotation unit |
Sf* |
tesla |
T |
torr |
Use millimeters of mercury. |
tuberculin unit |
TU |
turbidity-reducing unit |
TRU* |
unit |
U |
volt |
V |
volume |
vol |
volume per volume |
vol/vol |
volume percent |
vol% |
watt |
W |
week |
wk† |
weight |
wt |
weight per volume |
wt/vol |
weight per weight |
wt/wt |
yard |
yd |
year |
y† |
(*) Expand at first mention, with the abbreviation immediately following in parentheses. Abbreviate thereafter, except at the beginning of a sentence. (See also 18.3.4, Units of Measure, Format, Style, and Punctuation, Beginning of Sentence, Title, Subtitle.)
(†) Use the abbreviation only in a virgule construction and in tables and line art.