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Low Anion Gap Metabolic Acidosis

Anion Gap

Anion Gap

ANION GAP The Anion Gap is an approximate measurement of ions, that is molecules with a charge, either negative or positive. Sodium and potassium are positively charged and therefore called cations; this is why they are often represented as Na+ and K+ respectively. These two are the main cations measured in the blood. Negatively charged molecules are called anions, and the major anions measured in the blood are chloride (Cl–) and bicarbonate (HCO3–). You can tell those electrolytes in the blood because they are measured as mEq/L rather than in milligrams/dL. Because your body must remain neutral, or in other words having the same amount of positive ions as negative ions, the equation (Na+ + K+ + unmeasured cations) must = (Cl– + HCO3– + unmeasured anions). Some of the unmeasured cations (~7Mmol/L) include calcium, magnesium, and most other minerals. Unmeasured anions (~24 Mmol/L) include proteins like albumin, and phosphates, sulfates, etc. There are always more unmeasured anions than cations, and thus the “anion gap” equation, (Na+ + K+) – (Cl– + HCO3–), is always greater than zero. If your lab report does not include an anion gap, you can calculate it yourself by converting the CO2 result to HCO3– by subtracting 1 mEq/l from the CO2 content… Optimum Value: 10 to 12 MMol/L depending on the method of calculation. The Anion Gap is increased when there are excessive anions/acids in the blood. This is either from too much acid production or insufficient removal of acids (either through the lungs, stomach, or kidneys). Excess acids lead to a rapid respiratory rate (the body wants to blow off the extra CO2), an inability to hold your breath (the acid build up forces you to exhale), low blood pressure (due to vasodilation), fatigue, poor appetite, etc. T Continue reading >>

Anion Gap (blood) - Health Encyclopedia - University Of Rochester Medical Center

Anion Gap (blood) - Health Encyclopedia - University Of Rochester Medical Center

If you may have swallowed a poison, such as wood alcohol, salicylate (in aspirin), and ethylene glycol (in antifreeze), your provider may test your blood for it. If your provider thinks you have ketoacidosis, you might need a urine dipstick test for ketone compounds. Ketoacidosis is a health emergency. Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your healthcare provider. Results are given in milliequivalents per liter (mEq/L). Normal results are 3 to 10mEq/L, although the normal level may vary from lab to lab. If your results are higher, it may mean that you have metabolic acidosis. Hypoalbuminemia means you haveless albumin protein than normal. If you have this condition, your expected normal result must be lower. The test requires a blood sample, which is drawn through a needle from a vein in your arm. Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore. Being dehydrated or retaining water in your body can affect your results. Antibiotics such as penicillin can also affect your results. You don't need to prepare for this test. But be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use. Continue reading >>

Serum Anion Gap: Its Uses And Limitations In Clinical Medicine

Serum Anion Gap: Its Uses And Limitations In Clinical Medicine

Abstract 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 (ΔAG) and change in the serum bicarbonate concentration (ΔHCO3−) 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 ΔAG/ΔHCO3− 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 intoxication Continue reading >>

The Anion Gap

The Anion Gap

The anion gap is a tool used to: Confirm that an acidosis is indeed metabolic Narrow down the cause of a metabolic acidosis Monitor the progress of treatment In a metabolic acidosis the anion gap is usually either ‘Normal’ or ‘High’. In rare cases it can be ‘low’, usually due to hypoalbuminaemia. An ABG machine will often give a print out of the anion gap, but it can also be useful to know how it is calculated. In blood, there are many cations and anions. However, the vast majority of the total number are potassium, sodium, chloride, or bicarbonate. The ‘anion’ gap is an artificial measure, which is calculated by subtracting the total number of anions (negatively charged ions – bicarbonate and chloride) from the total number of cations (sodium and potassium). Thus, the formula is: ([Na+]+ [K+]) –([Cl–]+ [HCO3–]) In reality, the concentration of potassium anions is negligible, and this often omitted. There are usually more measurable cations than anions, and thus a normal anion gap is value is positive. A normal value is usually 3-16, but may vary slightly depending on the technique used by the local laboratory. If the anion gap is <30, then there may not be ‘true’ high anion gap metabolic acidosis. In a healthy normal individual, the main unmeasured anions are albumin and phosphate. Almost all of the gap can be attributed to albumin. This means that in patients with hypoalbuminaemia and metabolic acidosis, there may be a normal anion gap. Be wary in severely unwell patients because they often have a low albumin. You can adjust for this in your calculation. Corrected anion gap: [AG] + (0.25 x (40-albumin)) In an unwell patient with a high anion gap metabolic acidosis (HAGMA) the anion gap is increased due: Accumulation of organic acids Inabili Continue reading >>

Unusual Case Of Severe High Anion Gap Metabolic Acidosis | Clinical Kidney Journal | Oxford Academic

Unusual Case Of Severe High Anion Gap Metabolic Acidosis | Clinical Kidney Journal | Oxford Academic

We present a case of high anion gap metabolic acidosis with an unusual aetiology in a 75-year-old lady with hypoglycaemia, encephalopathy and relatively preserved renal function. Full toxicology and biochemical analysis suggested that she had an inborn error of metabolism, riboflavin-responsive multiple acyl-CoA dehydrogenase deficiency that can predispose to severe acidosis in situations where calorific intake is reduced. We believe this to be one of the few published cases and is remarkable for the presentation in late adulthood in addition to the requirement for emergency haemodialysis due to the severity of the metabolic disturbance. acyl carnitine , fatty acid metabolism , metabolic acidosis , riboflavin-responsive multiple acylCoA dehydrogenase deficiency A 75-year-old woman presented with a 9-day history of general malaise, anorexia and vomiting. She had consumed only lemonade and occasional soft diet for several weeks and became drowsy 24 h prior to admission. Her background medical history included schizophrenia and depression. She had been admitted to hospital 2 years previously with similar symptoms but had seizure activity as well as extreme metabolic acidosis requiring dialysis. Toxicology screening did not suggest common overdoses as a likely cause. At that time, she was extremely cachectic and a diagnosis of starvation ketoacidosis was made on the basis of exclusion and high serum levels of acetone. The initial step in fatty acid (FA) metabolism is the transfer of FA into the mitochondria for beta oxidation1. This requires the help of several mitochondrial enzymes that includes acyl-CoA dehydrogenase2 and carnitine acyltransferases2. rr-MADD is caused by defective transfer of electrons from primary flavoprotein dehydrogenases to the mitochondrial respira Continue reading >>

Serum Anion Gap In Conditions Other Than Metabolic Acidosis

Serum Anion Gap In Conditions Other Than Metabolic Acidosis

INTRODUCTION Determination of the serum anion gap (AG) is primarily used in the differential diagnosis of metabolic acidosis [1-4]. (See "Approach to the adult with metabolic acidosis", section on 'Physiologic interpretation of the serum anion gap'.) However, the serum AG can also become abnormal in other conditions, a finding that may be of diagnostic importance [1-5]. CALCULATION OF THE ANION GAP AND NORMAL VALUES The serum anion gap (AG) is calculated from the following formula: Serum AG = Measured cations - measured anions Since Na is the primary measured cation and Cl and HCO3 are the primary measured anions (calculator 1): Continue reading >>

Anion Gap Blood Test

Anion Gap Blood Test

What happens during an anion gap blood test? The anion gap test is taken from the results of an electrolyte panel, which is a blood test. During a blood test, a health care professional uses a small needle to take a blood sample from a vein in your arm. After the needle is inserted, a small amount of blood will be collected into a test tube. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes. Will I need to do anything to prepare for the test? You don't need any special preparations for an anion gap blood test. If your health care provider has also ordered other blood tests, you may need to fast (not eat or drink) for several hours before the test. Your health care provider will let you know if there are any special instructions to follow. There is very little risk to having this test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly. If your results show a high anion gap, you may have acidosis, which means higher than normal levels of acid in the blood. Acidosis may be a sign of dehydration , diarrhea , or too much exercise. It may also indicate a more serious condition such as kidney disease or diabetes . If your results show a low anion gap, it may mean you have a low level of albumin, a protein in the blood. Low albumin may indicate kidney problems, heart disease, or some types of cancer. Since low anion gap results are uncommon, retesting is often done to ensure the results are accurate. Talk to your health care provider to learn what your results mean. Is there anything else I need to know about an anion gap blood test? The anion gap blood test can provide important information about the acid and base balance in your blood. But there are a wide range Continue reading >>

Renal Fellow Network: Low Anion Gap

Renal Fellow Network: Low Anion Gap

Classically, we are taught to look out for an elevated anion gap in patients with a metabolic acidosis. Although much less common, a low anion gap can also be a useful sign and there are a variety of causes. The commonest cause is lab error, particularly in the measurement of the serum sodium. As previously discussed , high serum lipids or high serum proteins can lead to spuriously low serum sodium measurements thus altering the AG. Severe hypernatremia can also lead to errors in measuring the sodium concentration (usually underestimating the real result) and will lower the AG. Similarly, errors in measuring the chloride or the HCO3 will alter the perceived AG. The bicarbonate is usually measured indirectly and allowing the sample to sit without separating the cells can lead to increased production of CO2 and thus lower the AG. Apart from lab errors, the commonest cause of a low AG is due to alterations in serum protein levels. Most of the AG is due to negative charges on circulating proteins, primarily albumin so that if the albumin concentration falls, the AG will fall also. It is generally accepted that the AG should be corrected upwards by 2.5 for every 1g/dl fall in the serum albumin. This applies also for patients with an elevated serum albumin; the AG should be corrected downwards in that scenario. Although they do not normally contribute significantly to the AG, immunoglobulins can be important in patients with paraproteinemias. IgG tends to be cationic while IgA is an anion. Thus, patients with an IgG paraproteinemia and a high tumor burden can have a low or even negative AG. In contrast, patients with IgA paraproteinemia will have an elevated AG. Calcium and magnesium could theoretically decrease the AG if they are significantly increased. In practice, howeve Continue reading >>

Anion Gap - An Overview | Sciencedirect Topics

Anion Gap - An Overview | Sciencedirect Topics

The anion gap (AG) is the difference between the sum of the commonly measured cations and the sum of the commonly measured anions in serum, calculated as follows:AG=([Na+]+[K+])([Cl]+[HCO3]). Larry R. Engelking, in Textbook of Veterinary Physiological Chemistry (Third Edition) , 2015 The plasma anion gap is normally accounted for by proteins and other organic acids in the anionic form, phosphates, and sulfate. Hypoproteinemia causes a decrease in the anion gap. Normochloremic metabolic acidosis is usually associated with an increase in the anion gap. The plasma anion gap may not change in hyperchloremic metabolic acidosis. The urinary anion gap can be used to estimate the urine NH4+ concentration. The urinary anion gap, which is usually positive, may be negative in diarrheal disease. The urinary anion gap may not provide meaningful information when the urinary bicarbonate concentration in increased, or when ketone bodies appear in urine. Non-hypoproteinemic metabolic alkalosis is associated with an increase in the anion gap. In Clinical Veterinary Advisor: The Horse , 2012 Because total cations equal total anions in the blood, the anion gap indirectly represents the difference between unmeasured anions and unmeasured cations (UA UC). In health, major unmeasured anions include albumin, phosphates, sulfates, and small organic acids; unmeasured cations include calcium, magnesium, and gamma globulins. The latter are rarely ever increased enough to decrease the anion gap. Lactic acidosis (lactate), uremic acids, ketoacids (acetoacetate, -hydroxybutyrate), and ethylene glycol and propylene glycol metabolites Next Diagnostic Step to Consider if Levels High Measure lactate concentrations, evaluate renal function (blood urea nitrogen [BUN], creatinine, and electrolytes with con Continue reading >>

Anion Gap

Anion Gap

Pathophysiology sample values BMP/ELECTROLYTES: Na+ = 140 Cl− = 100 BUN = 20 / Glu = 150 K+ = 4 CO2 = 22 PCr = 1.0 \ ARTERIAL BLOOD GAS: HCO3− = 24 paCO2 = 40 paO2 = 95 pH = 7.40 ALVEOLAR GAS: pACO2 = 36 pAO2 = 105 A-a g = 10 OTHER: Ca = 9.5 Mg2+ = 2.0 PO4 = 1 CK = 55 BE = −0.36 AG = 16 SERUM OSMOLARITY/RENAL: PMO = 300 PCO = 295 POG = 5 BUN:Cr = 20 URINALYSIS: UNa+ = 80 UCl− = 100 UAG = 5 FENa = 0.95 UK+ = 25 USG = 1.01 UCr = 60 UO = 800 PROTEIN/GI/LIVER FUNCTION TESTS: LDH = 100 TP = 7.6 AST = 25 TBIL = 0.7 ALP = 71 Alb = 4.0 ALT = 40 BC = 0.5 AST/ALT = 0.6 BU = 0.2 AF alb = 3.0 SAAG = 1.0 SOG = 60 CSF: CSF alb = 30 CSF glu = 60 CSF/S alb = 7.5 CSF/S glu = 0.4 The anion gap[1][2] (AG or AGAP) is a value calculated from the results of multiple individual medical lab tests. It may be reported with the results of an Electrolyte Panel, which is often performed as part of a Comprehensive Metabolic Panel.[3] The anion gap is the difference between the measured cations (positively charged ions) and the measured anions (negatively charged ions) in serum, plasma, or urine. The magnitude of this difference (i.e., "gap") in the serum is often calculated in medicine when attempting to identify the cause of metabolic acidosis, a lower than normal pH in the blood. If the gap is greater than normal, then high anion gap metabolic acidosis is diagnosed. The term "anion gap" usually implies "serum anion gap", but the urine anion gap is also a clinically useful measure.[4][5][6][7] Calculation[edit] The anion gap is a calculated measure. This means that it is not directly measured by a specific lab test; rather, it is computed with a formula that uses the results of several individual lab tests, each of which measures the concentration of a specific anion or cation. The concentr Continue reading >>

Acid Base Flashcards | Quizlet

Acid Base Flashcards | Quizlet

2[Na] + [glucose/18] + [BUN/2.8]. If ethanol present, add (ethanol/4.6) to above equation Can cause both anion gap metabolic acidosis and metabolic alkalosis if has vomiting and normal PH, serum bicarbonate, and pCO2 Add 0.05 to abg ph if from central VBG. Add 0.03 to abg ph if from peripheral VBG Subtract 5 from central venous pCO2 to estimate arterial pCO2. Subtract 3-8 from peripheral pCO2 to estimate arterial pCO2 Methanol, uremia, DKA/Drugs (metformin, stavudine, topiramate), Phosphate/Paraldehyde, Ischemia/Isoniazid/Iron, Lactate, Ethylene glycol/ETOH, Starvation/salicylates For albumin. Add 2.5 to anion gap for every 1g/dl that serum albumin is decreased from 4 g/dl Diarrhea, Ureteral diversion, RTA, Hyperalimentation, Addison disease/ Acetazolamide/Ammonium chloride, Miscellaneous (Chloridorrhea, Amphotereicin B, Toluene) Bromism (ingestion of Bromo seltzer), Albumin low, Multiple Myeloma For every 1 that anion gap increases, serum bicarb drops 0.6 (Urine Na + urine K) - urine chloride. >0 means RTA 1 or 4. Caused by ingestion of osmotically active substances. Measured serum osm would be greater than calculated serum osm. Gap should be within 10. Wood alcohol, antifreeze. Delirium, papilledema, retinal hemorrhages, blurry vision Antifreeze. Delirium, oxalate crystals in urine Rubbing alcohol. Does not cause acid base disorder, when metabolized will show up as acetone in bloodstream. First causes elevated anion gap metabolic acidosis and then later normal anion gap metabolic acidosis as it results in renal tubular acidosis. Acid loss: vomiting, NG suction, over-diuresis, hypermineralcorticoid states ( conn's, Cushing), penicillins. HCO3 gain: administration of sodium bicarb, baking soda, citrate, lactate, acetate (liver converts all of these to bicarb) < 10 mEq/ Continue reading >>

Metabolic Acidosis - Endocrine And Metabolic Disorders - Merck Manuals Professional Edition

Metabolic Acidosis - Endocrine And Metabolic Disorders - Merck Manuals Professional Edition

(Video) Overview of Acid-Base Maps and Compensatory Mechanisms By James L. Lewis, III, MD, Attending Physician, Brookwood Baptist Health and Saint Vincent’s Ascension Health, Birmingham Metabolic acidosis is primary reduction in bicarbonate (HCO3−), typically with compensatory reduction in carbon dioxide partial pressure (Pco2); pH may be markedly low or slightly subnormal. Metabolic acidoses are categorized as high or normal anion gap based on the presence or absence of unmeasured anions in serum. Causes include accumulation of ketones and lactic acid, renal failure, and drug or toxin ingestion (high anion gap) and GI or renal HCO3− loss (normal anion gap). Symptoms and signs in severe cases include nausea and vomiting, lethargy, and hyperpnea. Diagnosis is clinical and with ABG and serum electrolyte measurement. The cause is treated; IV sodium bicarbonate may be indicated when pH is very low. Metabolic acidosis is acid accumulation due to Increased acid production or acid ingestion Acidemia (arterial pH < 7.35) results when acid load overwhelms respiratory compensation. Causes are classified by their effect on the anion gap (see The Anion Gap and see Table: Causes of Metabolic Acidosis ). Lactic acidosis (due to physiologic processes) Lactic acidosis (due to exogenous toxins) Toluene (initially high gap; subsequent excretion of metabolites normalizes gap) HIV nucleoside reverse transcriptase inhibitors Biguanides (rare except with acute kidney injury) Normal anion gap (hyperchloremic acidosis) Renal tubular acidosis, types 1, 2, and 4 The most common causes of a high anion gap metabolic acidosis are Ketoacidosis is a common complication of type 1 diabetes mellitus (see diabetic ketoacidosis ), but it also occurs with chronic alcoholism (see alcoholic ketoacidos Continue reading >>

Anion Gap

Anion Gap

The anion gap is the difference between primary measured cations (sodium Na+ and potassium K+) and the primary measured anions (chloride Cl- and bicarbonate HCO3-) in serum. This test is most commonly performed in patients who present with altered mental status, unknown exposures, acute renal failure, and acute illnesses. [1] See the Anion Gap calculator. The reference range of the anion gap is 3-11 mEq/L The normal value for the serum anion gap is 8-16 mEq/L. However, there are always unmeasurable anions, so an anion gap of less than 11 mEq/L using any of the equations listed in Description is considered normal. For the urine anion gap, the most prominently unmeasured anion is ammonia. Healthy subjects typically have a gap of 0 to slightly normal (< 10 mEq/L). A urine anion gap of more than 20 mEq/L is seen in metabolic acidosis when the kidneys are unable to excrete ammonia (such as in renal tubular acidosis). If the urine anion gap is zero or negative but the serum AG is positive, the source is most likely gastrointestinal (diarrhea or vomiting). [2] Continue reading >>

Low Anion Gap: Symptoms, Causes, Diagnosis

Low Anion Gap: Symptoms, Causes, Diagnosis

The anion gap is a value thats calculated using the results of an electrolyte blood test. Electrolytes are elements and compounds that occur naturally in the body and control important physiological functions. Calcium, chloride, magnesium, and sodium, among others, are electrolytes. Electrolytes have an electrical charge some are positive and others are negative. They help to control the balance of acids and bases in your body. The anion gap value is the difference between the negatively and positively charged electrolytes. If the calculated value for the anion gap is too high or too low, it may be a sign of a disorder. If your doctor suspects that you have an electrolyte imbalance in your blood, theyll order an anion gap blood test. The anion gap value is reported in units of milliequivalents per liter (mEq/L). Normal results generally fall between 3 and 10 mEq/L . However, normal ranges may vary by lab. A high anion gap value means that your blood is more acidic than normal. It may indicate that you have acidosis . Conditions that can cause acidosis (and therefore a high anion gap value) include: diabetic ketoacidosis , a condition requiring immediate medical attention Potential causes and diagnosisof a low anion gap Having a low anion gap value is very rare. The most common causes of low anion gap results may include the following. If your test indicates a low anion gap value, your doctor may order a second test to account for laboratory error. Because the anion gap is calculated from the results of the electrolyte panel, accurate measurement of the individual electrolytes is necessary. A published review found that out of 67,000 calculations of anion gap, a low anion gap was calculated less than 1 percent of the time. Within this small percentage, over 90 percent o Continue reading >>

Clinical Aspects Of The Anion Gap

Clinical Aspects Of The Anion Gap

The anion gap (AG) is a calculated parameter derived from measured serum/plasma electrolyte concentrations. The clinical value of this calculated parameter is the main focus of this article. Both increased and reduced anion gap have clinical significance, but the deviation from normal that has most clinical significance is increased anion gap associated with metabolic acidosis. This reflects the main clinical utility of the anion gap, which is to help in elucidating disturbances of acid-base balance. The article begins with a discussion of the concept of the anion gap, how it is calculated and issues surrounding the anion gap reference interval. CONCEPT OF THE ANION GAP - ITS DEFINITION AND CALCULATION Blood plasma is an aqueous (water) solution containing a plethora of chemical species including some that have a net electrical charge, the result of dissociation of salts and acids in the aqueous medium. Those that have a net positive charge are called cations and those with a net negative charge are called anions; collectively these electrically charged species are called ions. The law of electrochemical neutrality demands that, in common with all solutions, blood serum/plasma is electrochemically neutral so that the sum of the concentration of cations always equals the sum of the concentration of anions [1]. This immutable law is reflected in FIGURE 1, a graphic display of the concentration of the major ions normally present in plasma/serum. It is clear from this that quantitatively the most significant cation in plasma is sodium (Na+), and the most significant anions are chloride (Cl-) and bicarbonate HCO3-. The concentration of these three plasma constituents (sodium, chloride and bicarbonate) along with the cation potassium (K+) are routinely measured in the clinica Continue reading >>

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