Below is an instruction that describes a task. Write a response that appropriately completes the request. ### Instruction: Thank you for the response. Several months ago I did have elevated calcium but have been retested two times and calcium was normal. I was taking a lot of gas x and alka seltzer for the chest pain that I had gone in for.Also had bloodwork three weeks prior and anion gap and albumin and globulin were normal. Would that change so fast?. ### Response: Anion gap is calculated by (sodium + potassium) - (bicarbonate and chloride). Most of the time when it is reported as low it is because there is slight variation in these factors from any random blood sample leading it to be falsely low. This is why they usually repeat it, and usually it normalizes..