Anion Gap Calculator

How to use an Anion Gap Calculator And Why It Matters ?

The anion gap calculator is a biochemical test that measures the amount of bicarbonate in your blood. It’s commonly used as a screening tool to diagnose metabolic alkalosis, where you’ve been breathing more carbon dioxide than you’ve been able to eliminate through your lungs. If your result in the calculator is greater than 12, then the matter should be taken seriously.

This calculator will estimate how much CO2 is being released into the bloodstream and respiratory system by multiplying serum bicarbonate concentration with total CO2 to make the test easier and quicker.

This is the most accurate way to estimate the anion gap calculator because of the stoichiometry involved in balancing CO2 production in the body.

This calculator will also be affected by the amount of bicarbonate in your urine. For example, there will be more bicarbonate in your urine if you’ve recently eaten a salty meal or drunk alcohol than if you’ve had no other food for many hours before your test.

The same goes for CO2 production – the more carbon dioxide you’re breathing out, the less CO2 will be pulled into your body from bicarbonate intake.

How does anion gap calculator work?

When you get a reading for your anion gap calculator, the level of CO2 in your blood and tissues will be measured. The test uses an ion-selective electrode to measure the electrical potential of the CO2 that’s being released into the bloodstream and then measured by mass spectrometry.

CO2 in your blood is calculated based on this electrical measurement. You’ll get your answer in either mmol/L or ppm, which both mean millimoles and parts per million. Your urine is also tested, and again, the amount of bicarbonate found there can affect how your anion gap comes out.

This calculator uses the following assumptions:

  • The subject is breathing room air at sea level. If altitude or another anion gas calculator (such as heliox or nitrous oxide from a dental filling) is being breathed, adjust the concentrations accordingly. But please don’t be confused by thinking that a different quantity of CO2 will change the result; it will only change where you measure it on this calculator because these are both a function of each other.
  • When blood is taken, a heparin lock is put in place to prevent clotting (this will also note when a sample is “locked/locked”). This anion gas calculator uses 10 times the normal heparin concentration and will warn you if this is incorrect.
  • You entered a value for serum bicarbonate greater than 20 mmol/L (or 200 mmol/L) but less than 40 mmol/L (400 mmol/L). If you have entered a result that doesn’t match these criteria, you can use our calculator for normal anion gap calculation instead of this more spurious alternative.
  • The value is calculated only from blood samples. If you are using serum or plasma samples, please use the anion gas calculator from this article instead because the protein binding capacity of serum will dilute the sample and the fluid itself weighs far more than its volume.

What is the anion gap?

The anion gap is the difference between the number of negative ions in your blood and positive ions. The term “gap” refers to the space between charges on an atom, molecule, or ion.

This space can be as small as a single electron or as big as thousands of atoms or molecules. A number like -5 or +2 is thus a very big number, and we refer to this as an ionic charge.

What causes the anion gap?

    Many things affect the amount of bicarbonate in your blood and urine. Here are some of them:

  • The half-life of bicarbonate is around 2 hours. So if you’re having a blood test right before you go to bed, your bicarbonate level will be higher than normal because it was just being used by your cells and has been cleared by the kidneys for more than 2 hours.
  • The amount of bicarbonate in the blood and urine will vary with diet. Bicarbonate is a “secondary” anion gap that must be supplied by dietary intake, especially during times of high stress and during times of low dietary intake.

How to calculate the anion gap from serum bicarbonate concentration and CO2 in serum?

The only way to use the calculator is with a blood test. The blood sample will be weighed and then charged an electrode measures particles called ions on your hand.

These ions are what make up the electrolytes in your blood, and they carry a charge; the stronger the charge, the stronger their attraction to other charged particles, and so their concentration is directly proportional to how much of them there are in your blood.

The difference between a serum and plasma sample

The anion gas calculator Serum samples contain proteins that are not filtered by glomerulus; however, these proteins are not involved in an ion-exchange reaction.

Therefore, concentrations of Ag+and CHCO3- in serum are higher than those in separated plasma samples.

 What is a normal anion gap level?

The normal range for AG is 0-12 mEq/L. This can be used as a screening test to see if there’s a problem or not, but if your results show a high value, it may be indicative of heart disease or kidney failure.

 What diseases are associated with a high anion gap?

The most common cause of a high anion gap is a build-up of lactate; this can occur when the body is under stress, such as diabetic ketoacidosis, where the person may not get sufficient oxygen to the cells.

Alcohol withdrawal can also raise the anion gap, leading to cerebral metabolic acidosis and this is why you need to use an anion gap calculator.

 How do I lower my anion gap?

Generally, your anion gap will be lower if you have higher amounts of bicarbonate in your blood and urine because this means there is more buffer against changes in ph or increased CO2 that your body needs to breathe.


It is important to measure the anion gap using an anion gap calculator as a screening test for metabolic alkalosis. A calculator is a helpful tool that can help you do this.

There are side effects of the test when it is done incorrectly, so all physicians perform this test under the supervision of an anesthesiologist.

The anion gap calculator phenomenon has been established, but there are still questions about the relationship between metabolic acidosis and blood value.

It may be necessary to measure the gap in a patient with normal kidney function to determine if this is a real risk for him or her or if he or she has only a temporary metabolic alkalosis.


How do you calculate the anion gap from AG and serum bicarbonate?

The estimated anion gap  (eAG) can be calculated according to the following formula: eAG=AG-2 xCO2/22.4, where CO2 is the carbon dioxide concentration in serum and 22.4 is bicarbonate concentration in plasma (which might be slightly different from that in serum).

What is the difference between the anion gap and AG?

The amount of negative ions in your blood and urine is called the anion gap. The anion gap is the difference between the number of negative ions in your blood and positive ions. The term “gap” refers to the space between charges on an atom, molecule, or ion. This space can be as small as a single electron or as big as thousands of atoms or molecules. A number like -5 or +2 is thus a very big number, and we refer to this as an ionic charge.

Difference between the Anion Gap calculator and Anion Gap Index?

  The anion gap calculator index (AGI) is the ratio of the measured albumin concentration (expressed in g/dL) to the measured AG level (expressed in mEq/L). It can be calculated using the following formula: AGI=albumin/2.5 x AG x 10(-3), which means AGI can also be calculated with 2.5 g x 0.10(x -1).

Why do we use anion gap calculator and not AGI to diagnose the type of IDDM?

     The normal range for anion gap calculator is 12-16 mEq/L, and can be calculated from the following formula: AG = [Na] + [K]+ [Cl]- + [HCO3]-(or 0.8 times the albumin) where Na, K, Cl and HCO3 are measured in mEq/L by routine laboratory tests.

Why do we use anion gap calculator and not AGI to calculate Ag in patients with kidney disease?

    Normally, AGI is lower than 0.8 in patients with normal kidney function. However, it will be higher than 0.8 for patients with abnormal renal function. Therefore, the anion gap calculator is a more accurate way of calculating AG in these cases.

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