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.
