A low anion gap level is rare and indicates an abnormally high level of positively charged molecules. The most common cause of which, is multiple myeloma. Multiple myeloma is a cancer of a class of white blood cells called plasma cells. Typically, plasma cells help our bodies fight infection. In multiple myeloma, cancerous plasma cells accumulate in the bone marrow and crowd out health blood cells. The cancerous cells then produce abnormal proteins that cause kidney problems. This can result in an unusually high level of positively charged molecules.

An anion gap level of 20 or above signals a problem. The most likely issue is acidosis—too much acid in the blood. Acidosis can start in the kidneys or the lungs.

Metabolic Acidosis occurs when the kidneys can’t eliminate enough acid, or they are eliminating too much base. Poorly controlled diabetes can result in metabolic acidosis, as well as a lack of sodium in the body and an excess of lactic acid. A lack of sodium typically indicates diarrhea and / or vomiting. However, lactic acid buildup can be caused by chronic alcohol use, heart failure, cancer, seizures, liver failure, and prolonged exercise. Symptoms of metabolic acidosis:

- Rapid, shallow breathing

- Lack of appetite

- Jaundice (yellowing of skin and eyes)

- Increased heart rate

- Breath that smells fruity

Respiratory acidosis happens when there is too much CO2 in the body, because the lungs aren’t working properly.  Respiratory acidosis almost always results from a problem with the chest cavities of our bodies. These can include: injury to the chest, difficulty breathing caused by obesity, chronic airway conditions like asthma, muscle weakness in the chest, deformed chest structure, or overuse of alcohol.