milliequivalent per liter

(mEq/L)

A unit of measurement used for concentrations of solutions of substances with electrolytes.

(Comparison 1)
• mEq/L: One-thousandth of an equivalent of a chemical per liter.
• mmol/L: One-thousandth of a gram molecule per liter.

For example, for concentration of sodium, 1 mEq/L is the same as 1 mmol/L, because the number of equivalents of a sodium ion (Na+) is one. On the other hand, for concentration of calcium, 2 mEq/L is the same as 1 mmol/L, because the number of equivalents of a calcium ion (Ca2+) is two.

(Comparison 2)
• eq/L: Equivalent per liter.
• N: Normality or quivalent concentration.

The equivalent concentration of a solution (N) is defined as the molar concentration (mol/L) divided by an equivalence factor.
For example, for the concentration of sodium solution, 1 N equals to 1 mol/L, because the equivalence factor is 1 (Na+). On the other hand, for the concentration of calcium solution, 1 N equals to 2 mol/L, because the equivalence factor is 2 (Ca2+).