The most common cause of a low anion gap level is a lack of albumin protein in the blood, or hypoalbuminemia, when immunoglobulin levels are increased. Albumin is both a protein and an anion.Continue Reading
The anion gap, also called AG or AGAP, is calculated using the results of an electrolyte panel and each lab may use their own specific calculation. It is calculated using arterial blood.
A common method used to determine the anion gap is to add the number of chloride and bicarbonate anions and then subtract the amount from the total number of sodium and potassium cations. Another common method used by many hospitals is to subtract the total number of sodium and bicarbonate anions from the number of sodium cations only. As these methods illustrate, the anion gap is an estimated value. The normal range is considered to be between 8 and 16 mEq (or milliequivalents) per liter of blood.
If a subject has known albuminemia, then the values will be adjusted downwards. Other possible causes of a low anion gap value include hyponatremia, which indicates a low level of sodium in the blood, or multiple myeloma, a form of cancer of the bone marrow.Learn more about Human Anatomy