Common Cations and Anions in the body

Anion Gap calculation

(Na+K)-(Cl+CO2)

Anion Gap reference range

10-20 mmol/L (almost always posititve)

Sodium Normal range

135-145 mmol/L

Potassium normal range

3.4-5.0 mmol/L

Magnesium

4th most abundant cation in the body and 2nd most Intracellular Cation

Sodium

90% of extracellular Cations

Sodium critical values

<125 or >160 mmol/L

Bicarbonate

Anion In Extracellular fluid/ major component of total carbon dioxide

Acid/ base balance

Bicarbonate, Potassium, and Chloride

Blood coagulators

Calcium and Magnesium

Chloride

Chief extracellular Anion/ involved in maintaining osmolality and blood volume

Co-factors for enzymes

Magnesium, Zinc, Calcium, & Chloride

Potassium

Major intracellular Cation

Myocardial rhythm controllers

Potassium, Magnesium, & calcium

Neuromuscular excitablilty

Potassium, Magnesium, and Calcium

Volume and osmotic regulators

Sodium, Potassium and Chloride

Phosphate

anion found everywhere in living cells

Calcium

approx. 99% of calcium is in the bone and the other 1% is found in the blood and other extracellular fluids (cation)

Approx. 15% of calcium is...

bound to anions

Approx 45% of calcium is...

free or ionized calcium (not bound to proteins/ biologically active)

Lactate

is not specifically regulated

Electrolytes are highly regulated to...

maintain within the narrow ranges that are compatible with life

Decreased Anion Gap

may be seen in patients with decreased albumin or increased calcium levels (rare)

Increases Anion Gap

may be seen in patients with uremia/ renal failure

Approx 40% of calcium is...

protein bound