Denial code CO-151

What does Denial code CO-151 mean on a medical bill?

CO-151 means the plan paid for part of what was billed but not all of it, because the number of units or visits went past what its rules allow for that stretch of time. Read it as a quantity question rather than a coverage question: the service is covered, the count is what got trimmed. It also catches keying mistakes, like a unit typed with an extra digit. So the units on your itemized bill are the first thing to check, since a count that does not match your visit outranks any argument about the rule. The trimmed amount comes off under the provider's contract, which is what the CO letters mean.

What should I watch out for with Denial code CO-151?

• Ask the billing office for the itemized bill and check the unit count on the line the plan trimmed
• Ask whether a corrected claim is needed when the units billed do not match what you actually received
• Ask your plan what limit the line ran into and whether your doctor can request an exception to it