The Anion Gap

Prior, Anjali; Phillips, Patrick J.; Pain, Roy W.

doi:10.1016/s0140-6736(73)93039-0

Cited by 12 publications

(6 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Table 2 shows the mean and range of values for the serum anion gap based on data obtained from different clinical laboratories and reported in the literature. Variation in the mean and range of values among the studies reflect different methods of measuring the constituents: the values determined using either a continuous flow analyzer or ion-selective electrode (4,(16)(17)(18)(19)(20). Two facts stand out, particularly in the studies from the literature.…”

Section: Definition and Characterization Of The Normal Serum Anion Gapmentioning

confidence: 99%

The Serum Anion Gap in the Evaluation of Acid-Base Disorders

Kraut

Nagami

2013

Clinical Journal of the American Society of Nephrology

View full text Add to dashboard Cite

SummaryThe serum anion gap has been utilized to identify errors in the measurement of electrolytes, to detect paraproteins, and, most relevant to the nephrologist, to evaluate patients with suspected acid-base disorders. In regard to the latter purpose, traditionally an increased anion gap is identified when it exceeds the upper limit of normal for a particular clinical laboratory measurement. However, because there is a wide range of normal values (often 8-10 mEq/L), an increase in anion concentration can be present in the absence of an increased anion gap. In addition, the type of retained anion can affect the magnitude of the increase in anion gap relative to change in serum [HCO 3 2 ] being greater with lactic acidosis compared with ketoacidosis. This review examines the methods of calculation of the serum anion gap in textbooks and published literature, the effect of perturbations other than changes in acid-base balance, and its effectiveness in identifying mild and more severe disturbances in acidbase balance. Limitations of the present methods of determining the normal anion gap and change in the anion gap are highlighted. The possibility of identifying the baseline value for individuals to optimize the use of the calculation in the detection of metabolic acidosis is suggested.

show abstract

Section: Definition and Characterization Of The Normal Serum Anion Gapmentioning

confidence: 99%

The Serum Anion Gap in the Evaluation of Acid-Base Disorders

Kraut

Nagami

2013

Clinical Journal of the American Society of Nephrology

View full text Add to dashboard Cite

show abstract

“…Consequently, although the serum anion gap is calculated from the concentrations of Na ϩ , Cl Ϫ , and HCO 3 Ϫ , it also reflects the differences between the concentrations of unmeasured anions and cations. With the advent of automated analyzers that enabled measurement of electrolytes in large groups of individuals, the average level of the serum anion gap first was reported in the literature (1)(2)(3)10). The average serum anion gap in healthy individuals measured in mEq/L varied from 11 Ϯ 2.5 (range 6 to 16) (11) to 15 Ϯ 2.5 (range 10 to 20) (10) to 12 Ϯ 4 (range 8 to 16) (1)(2)(3)12).…”

Section: Determinants Of the Serum Anion Gapmentioning

confidence: 99%

“…Thus, the average anion gap and range of normal values will vary in different health care facilities, and it is essential that the clinician know the range of normal for the particular clinical laboratory to assess properly the changes in the serum anion gap. Furthermore, whichever methods are used for measurement of electrolytes, there is a wide range of normal values for the serum anion gap (reported normal values vary by as much as 6 to 10 mEq/L in individual clinical laboratories) (1,10,13,16), reflecting great interindividual variability. This variability, of course, must reflect the relatively wide range of normal values of each of its constituents.…”

Section: Determinants Of the Serum Anion Gapmentioning

confidence: 99%

“…Buckley-Sharp and Miller (10) found that it was a poor substitute for quality control of its individual constituents. By contrast, Witte et al (1) suggested that the serum anion gap provided a tool of comparing results of multiple determinations on a given patient, thereby offering an additional means of quality control.…”

Section: Low or Negative Serum Anion Gapmentioning

confidence: 99%

“…At this time, when a low value for serum anion gap is obtained, many clinical laboratories will repeat measurement of its constituents. However, most clinical laboratories do not depend on the serum anion gap to detect systematic or random errors in chemical determinations; rather, they depend primarily on determinations of individual electrolytes using reference samples (1,10,13).…”

Section: Low or Negative Serum Anion Gapmentioning

confidence: 99%

See 2 more Smart Citations

Serum Anion Gap

Kraut

Madias

2007

Clinical Journal of the American Society of Nephrology

327

257

View full text Add to dashboard Cite

The serum anion gap, calculated from the electrolytes measured in the chemical laboratory, is defined as the sum of serum chloride and bicarbonate concentrations subtracted from the serum sodium concentration. This entity is used in the detection and analysis of acid-base disorders, assessment of quality control in the chemical laboratory, and detection of such disorders as multiple myeloma, bromide intoxication, and lithium intoxication. The normal value can vary widely, reflecting both differences in the methods that are used to measure its constituents and substantial interindividual variability. Low values most commonly indicate laboratory error or hypoalbuminemia but can denote the presence of a paraproteinemia or intoxication with lithium, bromide, or iodide. Elevated values most commonly indicate metabolic acidosis but can reflect laboratory error, metabolic alkalosis, hyperphosphatemia, or paraproteinemia. Metabolic acidosis can be divided into high anion and normal anion gap varieties, which can be present alone or concurrently. A presumed 1:1 stoichiometry between change in the serum anion gap (⌬AG) and change in the serum bicarbonate concentration (⌬HCO 3 ؊ ) has been used to uncover the concurrence of mixed metabolic acid-base disorders in patients with high anion gap acidosis. However, recent studies indicate variability in the ⌬AG/⌬HCO 3 ؊ in this disorder. This observation undercuts the ability to use this ratio alone to detect complex acid-base disorders, thus emphasizing the need to consider additional information to obtain the appropriate diagnosis. Despite these caveats, calculation of the serum anion gap remains an inexpensive and effective tool that aids detection of various acid-base disorders, hematologic malignancies, and intoxications.

show abstract