Hi all, have a question about Medicare. Just received a bill from a local hospital for some lab work my late MIL had in July 2017. They billed Medicare part A/B $345.58. Medicare paid $33.77. They made an adjustment of -$150.81 and are demanding payment of $170. This hospital is in network if that makes a difference. We also have not received a statement from Medicare stating MIL could expect to pay this bill. My question is, aren’t they only allowed to bill the patient a maximum of 20%? Isn’t $170 more than 20%? All this Medicare stuff is confusing, I don’t know if it’s 20% of the entire bill or what Medicare paid. I don’t think she had medigap insurance (I’ve seen no evidence of it and unfortunately her box of important paperwork was pilfered by her partner before it was given to us and her insurance paperwork wasn’t there). Do we need to pay the entire $170 or can we fight this? Thank you!