Medicare denial CO - 45, PR 45, CO - 16, CO - 18,

Denial code co - 45 - Charges exceed your contracted/legislated fee arrangement. Note: This adjustment amount cannot equal the total service or claim charge amount; and must not duplicate provider adjustment amounts (payments and contractual reductions) that have resulted from prior payer(s) adjudication

CO should be sent if the adjustment is related to the contracted and/or negotiated rate.

134-Claim payment amt exceeds max allowed for mass adjudication

135-Claim payment amount exceeds the maximum allowed

CO45 with adjustment amount in excess of the limiting charge;

PR42 with the amount that is the difference between the allowed amount and the limiting charge for which the beneficiary is liable; if excess payment made by the beneficiary.

 Common Reasons for Message

    Item or service paid Medicare allowed amount
    Item or service paid to patient's deductible and/or coinsurance
    Item or services paid with partial unit


Explanation and solutions - It means that the billed which is more than Medicare allowed amount is adjustment. Just write it off.

Generally this code comes in paid claim. That means claims processed and allowed some amount, due to contract with Insurance we are not supposed to bill patient other than allowed amount. This amount is usually write off amount that what refers by CO 45.

For Example 

We have billed insurance CPT 99213 as billed amount of $100. In that insurance processed and paid $80 as allowed amount and remaining $20 is mentioned as CO 45 Which is going to be contractual adjustment as per the our contract with insurance.

Can we bill patient for PR 45 codes

PR 45 - Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement. Note: This adjustment amount cannot equal the total service or claim charge amount; and must not duplicate provider adjustment amounts (payments and contractual reductions) that have resulted from prior payer(s) adjudication

Though we could bill the patient when receive PR 45 code, its not good practice because we already billed more the customary rate.

Provider’s charge either exceeded contracted or negotiated agreement (rate, maximum number of hours, days or units) with the payer, exceeded the reasonable and customary amount for the rendered service(s). Use this category when a joint payer/payee agreement or a regulatory requirement has resulted in an adjustment that the member is not responsible for, or the provider’s charge exceeds the reasonable and customary amount and for which the patient is responsible.


PR should be sent if the adjustment amount is the patient’s responsibility. So we have to bill patient this is based on the scenario

Denial code co -16 - Claim/service lacks information which is needed for adjudication.

Explanation and solutions - It means some information missing in the claim form. This code always come with additional code hence look the additional code and find out what information missing. Resubmit the cliaim with corrected information.


This denial is little complicated denial, The claim was denied simply as Lack of Information need, with out knowing the exact reason for this denial we could not able to act on it. . Our primary responsible to check the remark code reason to get the exact reason for this denial.

For Example if the remark code is MA83 please find below for corrective measures for this denial.

MA83


Denial message

• Claim/service lacks information which is needed for adjudication (16)
• Did not indicate whether Medicare is primary or secondary payer (83)

Reason for denial

• The MSP type was not submitted in the 2000B, SBR, 05 (Insurance Type Code) field


How to resolve the denial

• Resubmit the claim with the appropriate MSP type in the Insurance Type Code field
• For a complete list of MSP types www.PalmettoGBA.com/bsc/resources
    o Select Medicare Secondary Payer
   o Electronic Claims – Valid MSP Types







Denial code co - 18 - Duplicate claim/service.

Explanation and solutions - It means that claim has been submitted more than once. Check the claim history if the submitted dates are small interval period then wait for original claim status or call IVR and find the original claims stats.



The most common codes used on the remits are from the CARC list, are alpha numeric (CO45 for example) and have specific meaning:

PR = Patient Responsibility

CO = Contractual Obligation (provider write-off )

OA = Other Adjustment (usually a previously paid amount or something similar)

1 comment:

Anonymous said...

Good Post

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