Processing Requirements

13. Bilateral Procedure 

There are codes that do not accurately reflect performed procedures in one admission on two or more different bilateral joints of the lower extremities. A combination of these codes show a bilateral procedure when, in fact, they could be single joint procedures (i.e., duplicate procedures). 

If two more of these procedures are coded, and the principal diagnosis is in MDC 8, the claim is flagged for post-pay development. The A/B MAC (A) processes the bill as coded but requests an O.R. report. If the report substantiates bilateral surgery, no further action is necessary. If the O.R. report does not substantiate bilateral surgery, an adjustment bill is processed. 

If the error rate for any provider is sufficiently high, the A/B MAC (A) may develop claims prior to payment on a provider-specific basis. 

Effective with the implementation of ICD-10, ICD-10-PCS codes will be implemented which clearly identify the exact joint (left or right). Reporting these two more precise ICD-10-PCS codes will clearly indicate if a bilateral procedure is performed.

14. Invalid Age 

If the hospital reports an age over l24, the A/B MAC (A) requests the hospital to determine if it made a bill preparation error. If the beneficiary's age is established at over l24, the hospital enters 123. 

15. Invalid Sex 

A patient's sex is sometimes necessary for appropriate MS-DRG determination. Usually the A/B MAC (A) can resolve the issue without hospital assistance. The sex code reported must be either 1 (male) or 2 (female). 

16. Invalid Discharge Status 

A patient's discharge status is sometimes necessary for appropriate MS-DRG determination. Discharge status must be coded according to the Form CMS-1450 conventions.

 17. Invalid Discharge Date 

An invalid discharge date is a discharge date that does not fall into the acceptable range of numbers to represent, either the month, day or year (e.g., 13/03/01, 12/32/01). If no discharge date is entered, it is also invalid. MCE reports when an invalid discharge date is entered. 

18. Limited Coverage 

Effective October 1, 2003, for certain procedures whose medical complexity and serious nature incur extraordinary associated costs, Medicare limits coverage. The edit message indicates the type of limited coverage (e.g., LVRS, heart transplant, etc). The procedures receiving limited coverage edits previously were listed as non-covered procedures, but were covered under Medicare in certain circumstances. The A/B MACs (A) will handle these procedures as they had previously. 

19. Procedure inconsistent with length of stay 

The following procedure code should only be coded on claims when the respiratory ventilation is provided for greater than four consecutive days during the length of stay. Effective October 1, 2012, ICD-9-CM procedure code, 96.72, Continuous invasive mechanical ventilation for 96 consecutive hours or more Effective October 1, 2015, ICD-10-PCS code, 5A1955Z - Respiratory Ventilation, Greater than 96 Consecutive Hours

Processing Requirements

9. Unacceptable Principal Diagnosis 

There are selected codes that describe a circumstance which influences an individual's health status but is not a current illness or injury; therefore, they are unacceptable as a principal diagnosis. For example, the diagnosis code for family history of a certain disease would be an unacceptable principal diagnosis since the patient may not have the disease. In a few cases, there are codes that are acceptable if a secondary diagnosis is coded. If no secondary diagnosis is present for them, MCE returns the message "requires secondary dx." The A/B MAC (A) may review claims with specific codes in the Unacceptable Principal Diagnosis section and a secondary diagnosis. A/B MACs (A) may choose to review as a principal diagnosis if data analysis deems it a priority. If these codes are identified without a secondary diagnosis, the A/B MAC (A) returns the bill to the hospital and requests a secondary diagnosis that describes the origin of the impairment. Also, bills containing other "unacceptable principal diagnosis" codes are returned. The hospital reviews the medical record and/or face sheet and enters the principal diagnosis that describes the illness or injury before returning the bill. 

10. Nonspecific O.R. Procedures 

Effective October 1, 2007 (FY 2008), the non-specific O.R. procedure edit was discontinued and will appear for claims processed using MCE version 2.0-23.0 only. 

11. Noncovered O.R. Procedures 

There are some O.R. procedures for which Medicare does not provide payment. The A/B MAC (A) will return the bill requesting that the non-covered procedure and its associated charges be removed from the covered claim, Type of Bill (TOB) 11X. If the hospital wishes to receive a Medicare denial, etc., the hospital may submit a non-covered claim, TOB 110, with the non-covered procedure/charges. 

12. Open Biopsy Check 

Biopsies can be performed as open (i.e., a body cavity is entered surgically), percutaneously, or endoscopically. The MS-DRG Grouper logic assign a patient to different MS-DRGs depending upon whether or not the biopsy was open. In general, for most organ systems, open biopsies are performed infrequently. 

Effective October 1, 1987, there are revised biopsy codes that distinguish between open and closed biopsies. To make sure that hospitals are using diagnosis codes correctly, the A/B MAC (A) requests O.R. reports on a sample of 10 percent of claims with open biopsy procedures for review on a post payment basis.

 If the O.R. report reveals that the biopsy was closed (performed percutaneously, endoscopically, etc.) the A/B MAC (A) changes the procedure code on the bill to the closed biopsy code and processes an adjustment bill. Some biopsy codes (3328 and 5634) have two related closed biopsy codes, one for closed endoscopic and for closed percutaneous biopsies. The A/B MAC (A) assigns the appropriate closed biopsy code after reviewing the medical information. 

Effective October 1, 2010, the open biopsy check edit was discontinued and was only used when processing MCE version 2.0 - 26.0. 

Effective with the implementation of ICD-10, ICD-10-PCS codes will be implemented which clearly identify in greater detail the approach used in the biopsy

Processing Requirements - Continued

5. Sex Conflict

The MCE detects inconsistencies between a patient's sex and a diagnosis or procedure on the patient's record. Examples are: 

• Male patient with cervical cancer (diagnosis). 

• Male patient with a hysterectomy (procedure). 

In both instances, the indicated diagnosis or the procedure conflicts with the stated sex of the patient. Therefore, either the patient's diagnosis, procedure or sex is incorrect. 

The MCE contains listings of male and female related diagnosis and procedure codes and the corresponding English descriptions. The hospital should review the medical record and/or face sheet and enter the proper sex, diagnosis, and procedure before returning the bill.

6. Manifestation Code 

As Principal Diagnosis A manifestation code describes the manifestation of an underlying disease, not the disease itself, and therefore, cannot be a principal diagnosis. The MCE contains listings of diagnosis codes identified as manifestation codes. The hospital should review the medical record and/or face sheet and enter the proper diagnosis before returning the bill. 

7. Nonspecific Principal Diagnosis

 Effective October 1, 2007 (FY 2008), the non-specific principal diagnosis edit was discontinued and will appear for claims processed using MCE version 2.0-23.0 only.

8. Questionable Admission

There are some diagnoses which are not usually sufficient justification for admission to an acute care hospital. 

The MCE contains a listing of diagnosis codes identified as "Questionable Admission" when used as principal diagnosis. 

The A/B MACs (A) may review on a post-payment basis all questionable admission cases. Where the A/B MAC (A) determines the denial rate is sufficiently high to warrant, it may review the claim before payment.

Processing Requirements

The hospital must follow the procedure described below for each error code. For bills returned to the provider, the A/B MAC (A) considers the bill improperly completed for control and processing time purposes.

NOTE: The following instructions are based on ICD-9-CM diagnosis and procedure codes. Applicable ICD-10-CM and ICD-10-PCS codes will be provided as part of the annual updates when ICD-10 is implemented. 

1. Invalid Diagnosis or Procedure Code 

The MCE checks each diagnosis code, including the admitting diagnosis, and each procedure code against a table of valid diagnosis and procedure codes. An admitting diagnosis, a principle diagnosis, and up to eight additional diagnoses may be reported. Up to six total procedure codes may be reported on an inpatient claim. If the recorded code is not in this table, the code is invalid, and the A/B MAC (A) returns the bill to the provider. 

For a list of valid diagnosis or procedure codes see the "International Classification of Diseases” revision applicable to the date of the inpatient discharge or other service and the "Addendum/Errata" and new codes furnished by the A/B MAC (A). The hospital must review the medical record and/or face sheet and enter the correct diagnosis/procedure codes before returning the bill.

2. External Cause of Injury Code as Principal Diagnosis 

External Cause of Injury codes describe the circumstances that caused an injury, not the nature of the injury, and therefore are not recognized by the Grouper program as acceptable principal diagnoses. In ICD-9-CM the external cause of injury diagnosis codes begin with the letter E. In ICD-10-CM the external cause of injury codes begin with the letters V, W, X and Y. For a list of all External cause of injury codes, see "International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM), January 1979, Volume l (Diseases)" and the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM). The hospital must review the medical record and/or face sheet and enter the correct diagnosis before returning the bill.

3. Duplicate of PDX 

Any secondary diagnosis that is the same code as the principal diagnosis is identified as a duplicate of the principal diagnoses. This is unacceptable because the secondary diagnosis may cause an erroneous assignment to a higher severity MS-DRG. Hospitals may not repeat a diagnosis code. The A/B MAC (A) will delete the duplicate secondary diagnosis and process the bill.

4. Age Conflict

The MCE detects inconsistencies between a patient's age and any diagnosis on the patient's record. Examples are:

 • A 5-year-old patient with benign prostatic hypertrophy. 

• A 78-year-old delivery. 

In the above cases, the diagnosis is clinically impossible in a patient of the stated age. Therefore, either the diagnosis or age is presumed to be incorrect. Four age code categories are described below.

• A subset of diagnoses is intended only for newborns and neonates. These are "Newborn" diagnoses. For "Newborn" diagnoses, the patient's age must be 0 years. 

• Certain diagnoses are considered reasonable only for children between the ages of 0 and 17. These are "Pediatric" diagnoses. 

• Diagnoses identified as "Maternity" are coded only for patients between the ages of l2 and 55 years.

• A subset of diagnoses is considered valid only for patients over the age of 14. These are "Adult" diagnoses. For "Adult" diagnoses the age range is 15 through 124.