ICD-9-CM – Selection of Principal Procedure

In the fourth quarter AHA Coding Clinic for ICD-9-CM the reporting of the principal procedure is clarified. Prior to this coding clinic the definition of the principal procedure was ambiguous and open to interpretation. The reason why this is important, especially for certified medical coders, is because the assignment of the correct principal procedure can affect the DRG that is assigned. This in turn can affect the reimbursement that is provided.

This coding clinic provides the following four instructions for the selection of the principal procedure.

1. Procedure performed for definitive treatment of both principal diagnosis and secondary diagnosis.Sequence procedure performed for definitive treatment most related to principal diagnosis as principal procedure.
2. Procedure performed for definitive treatment and diagnostic procedures performed for both principal diagnosis and secondary diagnosis.Sequence procedure performed for definitive treatment most related to principal diagnosis as principal procedure.
3. A diagnostic procedure was performed for the principal diagnosis and a procedure is performed for definitive treatment of a secondary diagnosis.Sequence diagnostic procedure as principal procedure, since the procedure most related to the principal diagnosis takes precedence.
4. No procedures performed that are related to principal diagnosis; procedures performed for definitive treatment and diagnostic procedures were performed for secondary diagnosis.Sequence procedure performed for definitive treatment of secondary diagnosis as principal procedure, since there are no procedures (definitive or non-definitive treatment) related to principal diagnosis.

It is also important to be familiar with the definition of the principal diagnosis to assist you in selecting the correct principal procedure. The definition of the principal diagnosis is the condition established after study to be chiefly responsible for occasioning the admission of the patient to the hospital for care. When a medical coder correctly assigns the principal diagnosis this will help in determining the correct principal procedure.

The opposite of this is also true. The assignment of the incorrect principal diagnosis can lead to the assignment of the incorrect principal procedure. As mentioned early this can affect the reimbursement that is provided. Because of this it is essential that a medical coder assign the correct principal diagnosis and principal procedure. Incorrect assignment of these can lead to higher or lower reimbursement for the services provided to the patient.

In order to correctly assign the principal diagnosis and principal procedure the medical coder needs to review the entire inpatient record. You cannot take shortcut when you are coding inpatient records. There are examples about the assignment of the principal procedure in the fourth quarter AHA Coding Clinic for ICD-9-CM. We encourage you to review the examples in this coding clinic to get a better understanding of the correct assignment of the principal procedure.