If you have a collection account on your credit reports, chances are pretty good it’s from a medical bill. And chances are also good that the collection is having an outsized impact on your credit scores.

Today the Consumer Financial Protection Bureau released a study saying credit scores unfairly penalized people with medical collections. Those scores underestimated the creditworthiness of such people by 16 to 22 points, according the bureau’s review of 5 million people’s credit reports.

The byzantine way medical care is bought and paid for in the U.S. contributes to the problem. Even if you’re insured, it’s easy for a medical bill to slip through the cracks.

“Sometimes insurance does not cover everything.  Sometimes [people] do not know what they owe because of how complicated the billing process can be,” CFPB Director Richard Cordray noted in a prepared statement.  “Other times they may not even know they owe anything, thinking that their insurance will cover the bill.  Sometimes the debt is caused by billing issues with medical providers or insurers.  Complaints to the Bureau indicate that many consumers do not even know they have a medical debt in collections until they get a call from a debt collector or they discover the debt on their credit report.”

FICO, creators of the leading credit score, have already tweaked the formula to ignore collections under $100. The next version of the score, FICO 9, will use “a more nuanced approach to assessing consumer collection data,” promised spokesman Anthony Sprauve. With this formula, scheduled to be released later this year, “medical collections will have a smaller impact than non-medical collections.”

The problem, as credit industry insiders will tell you, is that most lenders continue to use older versions of the FICO formula that don’t have these upgrades. So even though FICO concedes the point that medical bills aren’t as predictive as other types of collections, they can still unfairly wallop your scores.