Emergency Room Visit $1400 over estimate provided?

I had to visit the emergency room early in September (after first going to an urgent care) due to severe symptoms from what we eventually learned to be a combo of salmonella and norovirus. I was in the ER for a couple of hours, during which time I was given an IV bag of saline for dehydration, blood and urine tests, and an precautionary EKG. The billing coordinator came in during the visit and said that the estimate of my obligation was $198, which I paid. Now I'm receiving a bill for an additional $1400. The EOB is correctly done on my insurance account (30% coinsurance after deductible, which I have not met yet, so I am responsible for the billed amount), but I'm surprised and confused why the billed amount is so significantly higher than the estimate provided. Is this standard practice for emergency room visits? What are my options to ensure that I have been billed correctly? Thank you very much for any and all guidance.

submitted by /u/southpaw8265
[comments]