The normal range fo r the serum anion gap is rela tively. Rationale although most clinical data are prospective, they are scarce and observational. Complex acidbase disorders robert m centor, md facp. The anion gap is a useful calculation in assessing metabolic acidosis. The anion gap calculator evaluates states of metabolic acidosis. Clinical chemistry, immunology and laboratory quality control, 2014. Hypoalbuminemia is the most common cause of a low anion gap. This indicates a combined anion gap metabolic acidosis plus a nonaniongap metabolic acidosis.
Determining if a patients acidosis also has an elevated anion gap. Clinical journal of the american society of nephrology. Review of the diagnostic evaluation of normal anion gap metabolic. Pdf metabolic acidosis is characterized by a primary reduction in serum bicarbonate hco3 concentration, a secondary decrease in the arterial. More discussion of the anion gap in the chapter on diagnosing acid base problems here. Diagnosis of metabolic acidbase disorders emcrit project. The anion that replaces the titrated bicarbonate is chloride and because. Anion gap is defined as the difference between measured cations sodium and potassium and anions chloride and bicarbonate in serum. The anion gap in the serum is useful in the interpretation of acidbase disorders and in the.
The anion gap is the difference between certain measured cations positively charged ions and the measured anions negatively charged ions in serum, plasma, or urine. Clinical usefulness of the serum anion gap koreamed synapse. Normal anion gap metabolic acidosis is a com mon but often misdiagnosed clinical. The difference between measur able cations and anions, known as anion gap, helps to classify the severity of acidosis. In hyperchloraemic acidosis, the aniongap is normal in most cases. This reveals a combination of an anion gap metabolic acidosis plus a metabolic alkalosis. Chapter 9 metabolic effects of citrate based versus bicarbonate. A high anion gap suggests metabolic acidosis ketoacidosis, lactic acidosis. We now have an abg analyzer to help with acidbase analysis as well. Suspect in any patient with a non anion gap acidosis, very low serum hco3 and a urine ph that is inappropriately high above 5. A quick reference on high anion gap metabolic acidosis. Nothing fancy, no corrections for anything glucose, albumin, potassium, etc.
Elevated anion gap is concerning, because many causes of this are immediately lifethreatening. The experts suggest that the urinary anion gap should only be calculated in metabolic acidosis without unmeasured anions or obvious etiology. High anion gap metabolic acidosis hagma is a subcategory of acidosis of metabolic i. Increased anion gap metabolic acidosis as a result of 5oxoproline pyroglutamic acid. This is because a normal anion gap spans a range of 10 mm. The anion gap ag helps differentiate causes of metabolic acidosis into those associated with a normal ag hyperchloremic acidosis and those associated. High anion gap metabolic acidosis is a form of metabolic acidosis characterized by a high anion gap a medical value based on the concentrations of ions in a patients serum. Need to have an unexplained non anion gap metabolic acidosis i. Engelking, in textbook of veterinary physiological chemistry third edition, 2015. Metabolic acidosis occurs when the body produces too much acid, or when the kidneys are not removing enough acid from the body.