_id

683a15f8c782e11e38d1b0dd

id

1669

title

Serum Anion Gap

full_title

Serum Anion Gap

short_title

Anion Gap

med_description

Evaluates states of metabolic acidosis.

short_description

Evaluates states of metabolic acidosis.

slug

anion-gap

description

The Serum Anion Gap calculator evaluates states of metabolic acidosis.

keywords

Anion Gap, anion gap calc, acidosis calc, metabolic acidosis, metabolic acidosis calc, acidosis anion gap, anion gap acid, anion gap metabolic acidosis, metabolic acidosis calculator, delta ratio, delta ratio calc, anion gap interpretation, anion gap score, anion gap mdcalc, acidosis calculator, acidosis delta gap, anion gap delta ratio, anion sodium, anion chloride, anion bicarbonate, metabolic acidosis, metabolic acidosis anion gap, metabolic anion, bicarb anion gap, bicarb acidosis, anion gap calculation, delta ratio anion, hardups, anion hardups, anion respiratory, anion gap respiratory, respiratory acidosis, resp acidosis anion gap, alkalosis anion gap, elevated anion gap, increased anion gap

complaint

[ "AMS", "Shortness of Breath", "Vomiting" ]

formula

Key formulas include: Anion Gap = Na - (Cl + HCO3-) or Anion gap, mEq/L = sodium, mEq/L - (chloride, mEq/L+ bicarbonate, mEq/L) Delta Gap = the patient’s Anion Gap – the “normal” anion gap (considered to be 10 to 12) Albumin corrected anion gap, mEq/L = anion gap + [ 2.5 × (4 - albumin, g/dL) ] Albumin corrected delta gap, mEq/L = albumin corrected anion gap - “normal” anion gap (considered to be 10 to 12) Delta ratio = delta anion gap / (24 - bicarbonate, mEq/L) Albumin corrected delta ratio = albumin corrected delta gap / (24 - bicarbonate, mEq/L)

evidence

measurements

[ { "name": "Bicarbonate", "unit": "bicarb", "error_min": "1", "error_max": "100", "warn_min": "4", "warn_max": "60", "conversion": "1", "normal_max_si": "28", "normal_max_us": "28", "normal_min_si": "23", "normal_min_us": "23", "units_si": "mmol/L", "units_us": "mEq/L" }, { "name": "Chloride", "unit": "cl", "error_min": "70", "error_max": "130", "warn_min": "80", "warn_max": "120", "conversion": "1", "normal_max_si": "106", "normal_max_us": "106", "normal_min_si": "98", "normal_min_us": "98", "units_si": "mmol/L", "units_us": "mEq/L" }, { "name": "Sodium", "unit": "na", "error_min": "100", "error_max": "200", "warn_min": "0", "warn_max": "170", "conversion": "1", "normal_max_si": "145", "normal_max_us": "145", "normal_min_si": "136", "normal_min_us": "136", "units_si": "mmol/L", "units_us": "mEq/L" }, { "name": "Albumin (General)", "unit": "alb", "error_min": "0", "error_max": "7", "warn_min": "1", "warn_max": "6", "conversion": "10", "normal_max_si": "55", "normal_max_us": "5.5", "normal_min_si": "35", "normal_min_us": "3.5", "units_si": "g/L", "units_us": "g/dL" } ]

information

Interpretation:

The delta ratio is the ratio of the amount of additional anion in a body to the amount of additional H⁺. The anion's volume of distribution and its excretion affect this ratio. Organic acids with a greater distribution may produce lower anion gaps compared to inorganic acids, which may be confined to the extracellular compartment.

refrences

{ "Clinical Practice Guidelines": [ { "href": "", "text": "" } ], "Manufacturer Website": [ { "href": "", "text": "" } ], "Original/Primary Reference": [ { "href": "https://www.ncbi.nlm.nih.gov/pubmed/895822", "text": "Oh MS, Carroll HJ. The anion gap. N. Engl. J. Med. 1977; 297 (15): 814–7.doi:10.1056/NEJM197710132971507. PMID 895822" } ], "Other References": [ { "href": "https://link.springer.com/chapter/10.1007/978-0-387-77452-7_35", "text": "Criner GJ. Metabolic Disturbance of Acid-Base and Electrolytes. In: Critical Care Study Guide: Text and Review. 2nd ed. Philadelphia, PA: Springer; 2010:696." }, { "href": "https://www.ncbi.nlm.nih.gov/pubmed/25295502", "text": "Berend K, De vries AP, Gans RO. Physiological approach to assessment of acid-base disturbances. N Engl J Med. 2014;371(15):1434-45." } ], "Outcomes": [ { "href": "", "text": "" } ], "Validation": [ { "href": "", "text": "" } ], "Validations": [] }

pearls

• A “normal” anion gap value assumes that unmeasured proteins with charges (e.g., immunoglobulins with positive charges, albumin with a negative charge) are within their respective reference ranges. 
• Patients with low albumin or elevated immunoglobulins may have a lower baseline anion gap, which can obscure the recognition of an increased anion gap in the setting of acidosis. 

usecase

Use to determine if a patient's metabolic acidosis also has an elevated anion gap.

reasons

Acidosis with an increased anion gap has a distinct differential diagnosis compared to non-gap acidosis.

next_advice

In cases of hypoalbuminemia or hyperalbuminemia, the corrected anion gap result may be more accurate. 

If no albumin is entered, or if albumin is within the normal range, no correction is necessary. 

next_actions

next_management

Management of an anion gap acidosis focuses on correcting the underlying cause and varies based on the specific etiology.

Anion Gap Metabolic Acidosis: MUDPILERS

• Methanol

• Uremia

• Diabetic ketoacidosis/alcoholic ketoacidosis

• Paraldehyde

• Isoniazid

• Lactic acidosis

• Ethanol/ethylene glycol

• Rhabdomyolysis/renal failure

• Salicylates

Non-Anion Gap Acidosis: HARDUPS

• Hyperalimentation

• Acetazolamide

• Renal tubular acidosis

• Diarrhea

• Uretero-pelvic shunt

• Post-hypocapnia

• Spironolactone

Acute Respiratory Acidosis: 

• CNS depression (drugs/CVA)

• Airway obstruction

• Pneumonia

• Pulmonary edema

• Hemo/pneumothorax

• Myopathy

Chronic Respiratory Acidosis:

• COPD
• Restrictive lung disease
• Any hypoventilation state

Metabolic Alkalosis: CLEVER PD

• Contraction

• Licorice

• Endocrine causes (Conn's, Cushings, or Bartter's Syndrome)

• Vomiting

• Excess alkali

• Refeeding alkalosis

• Post-hypercapnia

• Diuretics

Respiratory Alkalosis: CHAMPS (think speed up breathing)

• Central Nervous System (CNS) disease

• Hypoxia

• Anxiety

• Mechanical ventilators

• Progesterone

• Salicylates/sepsis

diseases

[ "Acid-Base Disturbance", "Diabetes Mellitus", "Ingestion/Overdose", "Renal Failure", "Sepsis" ]

input_schema

[ { "conditionality": "", "default": null, "fhir_rules": null, "inct": null, "label_en": "Sodium", "name": "sodium", "optional": false, "tips_en": "", "type": "textbox", "unit": "na" }, { "conditionality": "", "default": null, "fhir_rules": null, "inct": null, "label_en": "Chloride", "name": "chloride", "optional": false, "tips_en": "", "type": "textbox", "unit": "cl" }, { "conditionality": "", "default": null, "fhir_rules": null, "inct": null, "label_en": "Bicarbonate", "name": "bicarbonate", "optional": false, "tips_en": "", "type": "textbox", "unit": "bicarb" }, { "conditionality": "", "default": null, "fhir_rules": null, "inct": null, "label_en": "Albumin", "name": "albumin", "optional": true, "tips_en": "", "type": "textbox", "unit": "alb" } ]

instructions

We also have an ABG Analyzer to help with acid-base analysis.

published

2022-04-21T20:28:58.249Z

purpose

[ "Diagnosis", "Formula" ]

search_terms

[ "acidosis", "ph", "delta ratio", "sodium", "chloride", "bicarbonate", "ions", "metabolic acidosis" ]

seo

{ "keywords_en": "Anion Gap, anion gap calc, acidosis calc, metabolic acidosis, metabolic acidosis calc, acidosis anion gap, anion gap acid, anion gap metabolic acidosis, metabolic acidosis calculator, delta ratio, delta ratio calc, anion gap interpretation, anion gap score, anion gap mdcalc, acidosis calculator, acidosis delta gap, anion gap delta ratio, anion sodium, anion chloride, anion bicarbonate, metabolic acidosis, metabolic acidosis anion gap, metabolic anion, bicarb anion gap, bicarb acidosis, anion gap calculation, delta ratio anion, hardups, anion hardups, anion respiratory, anion gap respiratory, respiratory acidosis, resp acidosis anion gap, alkalosis anion gap, elevated anion gap, increased anion gap", "meta_description_en": "The Serum Anion Gap calculator evaluates states of metabolic acidosis." }

specialty

[ "Critical Care", "Emergency Medicine", "Endocrinology", "Hospitalist Medicine", "Internal Medicine", "Nephrology", "Toxicology" ]

departments

[ "Endocrine and Metabolic", "Renal" ]

tags

[]

version_number

1

versions

[]

related

[ { "calcId": 1741, "short_title_en": "ABG Analysis", "slug": "arterial-blood-gas-abg-analyzer" }, { "calcId": 117, "short_title_en": "Winters' Formula", "slug": "winters-formula-metabolic-acidosis-compensation" }, { "calcId": 2045, "short_title_en": "Urine Anion Gap", "slug": "urine-anion-gap" } ]

ismed

false

section

[ "whenToUseViewed", "pearlsPitfallsViewed", "whyUseViewed", "nextStepsViewed", "evidenceViewed" ]

cleaned_departments

[ "endocrine", "urology" ]

cleaned_use

[ "Use to determine if a patient's metabolic acidosis also has an elevated anion gap." ]

pub

true