In the US, most laboratory test results are reported in what are termed conventional units; the rest of the world reports results inSystème International d’Unités(SI) or international units (IU). The unit basis for SI is updated periodically by a panel.
Many SI units are the same as units used in the US system; however, SI units for concentrations are not. SI concentrations are reported as moles (mol) or decimal fractions of a mole (eg, millimole, micromole) per unit volume in liters (L). Conventional units are reported as mass (eg, grams, milligrams) or chemical equivalency (eg, milliequivalents) per unit volume, which may be in liters or decimal fractions of liters (eg, deciliters, milliliters). Results reported in amount per 100 mL (1 dL) are sometimes expressed as percent (eg, 10 mg/dL may be written as 10 mg%).
Moles, milligrams, and milliequivalents:摩尔是an Avogadro’s number (6.023×1023) of elementary entities (eg, atoms, ions, molecules); the mass of 1 mole of a substance is its atomic weight in grams (eg, 1 mole of sodium=23 g, 1 mole of calcium=40 g). Similarly, the mass of a given quantity of substance divided by its atomic weight gives the number of moles (eg, 20 g sodium=20/23，或0.87，mol）。
等效的是整合电荷和痣的单位；1等效代表一摩尔的电荷，并通过在物质中乘以带电颗粒的摩尔数量来计算该物质的价值。因此，对于带有一个的离子+1 or−1 charge (eg, Na+, K+, Cl−），1摩尔是1等效的（1个×1=1); for ions with a+2 or−2 charge (eg, Ca2+), ½ mole is 1 equivalent (½×2=1), and so forth for other valence values. A milliequivalent (mEq) is 1/1000 of an equivalent.
The following can be used to convert between mEq, mg, and mmol:
meq=mg/formula wt×valence=mmol×valence
mg=meq×formula wt /valence=mmol×formula wt
mmol=mg/formula wt=meq/valence
(Note: Formula wt=atomic or molecular wt.)
Alternatively, conversion tables are available in print and on the Internet.
