It's important to note that the discounted rate for your in-network doctor or other provider should be the starting point for any coinsurance or deductible you are responsible for.
For example, if the doctor's full rate is $200 and the discounted cost is $100, the lower price is what would count against any deductible you have to meet. Or if you have coinsurance of, say, 20 percent, you're responsible for that percentage of $100, not $200.
"Sometimes there's the mistake of not basing your share on the discounted rate," Vitals.com's Rothschild said.
Coding errors also can be the culprit. For instance, if a routine screening that is 100 percent covered by your insurance plan is coded incorrectly, your insurer might note on the EOB that you owe the full amount.
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If you believe there's an error on your EOB, you should start by calling your insurance company, said Conley at Medliminal.com.
"If the claim was processed incorrectly, they'll get on a conference call with your provider to correct the billing," she said.
Some companies offer billing advocacy services for workers who need help making sense of their bill or getting errors fixed. If your employer has this perk, take advantage of it. You also can hire a specialized advocacy firm, which typically reviews bills for free and takes a cut of whatever amount they save you.
Even if everything on an EOB looks accurate, make sure you hold on to it to compare with the bill you get from your provider before you pay it. Sometimes, the doctor's bill will say you owe a higher amount than what's on the EOB.
"Go by what the insurance company says, not the bill," said Jeanne Woodward, vice president of consumer claims at Medliminal.
Errors tend to be more prevalent when you end up in the hospital. Due to the variety of doctors who tend to you and tests or procedures ordered, there can be many different individual providers that end up filing a claim with your insurance company.
"Inevitably, there will be mistakes," Rothschild said.