Q. Is an anion gap of 20 mmol/L bad?

Answered by
Dr. Sagar Ramesh Makode
and medically reviewed by iCliniq medical review team.
This is a premium question & answer published on May 21, 2017 and last reviewed on: Sep 23, 2021

Hello doctor,

I am a 32 year old female, and I went to the ER four days back for SVT. Apparently, my anion gap was 20 mmol/L. Is this bad? The BUN was less than 3, ionized calcium was 1.11 and low creatinine. I am freaking out as no one went over the results with me. I have had four cases of SVT recently, and I am now really worried about these test results.



Welcome to

Firstly, low BUN (blood urea nitrogen) and creatinine levels are not a matter of worry. Normal BUN range is from 2.5 to 7.1 mmol/L. Also, ionized calcium is a bit lower but still normal.

Anion gap is high, but it has got significance if you have acidosis as well low pH. If you read it on a printed ABG (arterial blood gas) or VBG (venous blood gas) report, then it is inaccurate most of the times. Also, creatinine and BUN report on the printed report are rarely accurate. So, nobody usually pays attention to that. And if the clinical scenario is suspicious, then assays are done and anion gap is calculated manually.

Next, regarding SVT (supraventricular tachycardia), it is probably not related to your above reports. It is arrhythmias caused by extra pathways in the heart. They are rarely life threatening but cause symptoms.

There are two options as follows.

  1. Continue medicine like beta blockers like Metoprolol or calcium channel blockers like Diltiazem. This will get the SVT under control, but it needs to be continued lifelong.
  2. You can undergo electrophysiological studies, which is a minor procedure where a wire is inserted up to the heart and arrhythmia is treated permanently in most of the cases.

It is better if you can upload ECG showing SVT, so as to know what type of SVT it is.

Hope this helps you, and get back if you have any doubts.

Revert with more information to an internal medicine physician online -->

Hi doctor,

Thank you so much. I feel much better. After finding online calculators, it looks like my anion gap is 16, which can be considered normal. High but normal, so I am no longer scared. Thank you very much for the information on the SVT. I feel a lot better and you helped me get rid of my fears. 



Welcome back to

You are welcome. All the best.

For further queries consult an internal medicine physician online -->

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