In all medical coding facility, ICD codes play a very important role. The sequencing of diagnosis codes should be correct for proper payment of the Procedure. As a medical coder, I have seen how coders struggle to code the ICD 10 diagnosis codes.

Today, I am just here to share my knowledge on coding the primary diagnosis. When there are multiple diagnosis codes in a medical report, medical coders struggle to choose primary diagnosis and secondary diagnosis. Sometimes even the coders have confusion in coding admit diagnosis, Reason for Visit(ROS) and primary diagnosis.

How to choose Primary diagnosis in Medical coding

Read also: Top Common Mistakes in ICD 10 coding

Difference in Admit diagnosis, ROS and Primary diagnosis

If you are reporting codes in a coding software like 3M, there are three columns for coding diagnosis. The admit diagnosis, ROS and Primary diagnosis are the three section for coding diagnosis. Here, the admit diagnosis and ROS will have same codes. The primary diagnosis will be coded as per the conclusion of the medical report. Let us learn with an example.

A patient comes with an abdominal pain (R10.9) to a physician and the physician performs an abdominal Ultrasound complete (76700). After the exam, the physician reports a colon diverticulosis (K57.30) as confirmed diagnosis in the medical report, then you will have to code the report as shown below.

Admit diagnosis: R10.9

ROS: R10.9

Primary diagnosis: K57.30



Read also: New ICD 10 coding guidelines for Z3A category in 2018

Selecting First listed or Primary Diagnosis

Now let us take one more example. I know most of the coders have the problem with coding neoplasm. Let us say, a patient is admitted for a primary malignant neoplasm of ovary (C56.9) and the physician is directing its treatment towards secondary malignant neoplasm of bone (C79.51). In such cases the primary diagnosis will the secondary neoplasm of bone, even though the primary neoplasm is present.

If the situation was reverse, the patient was admitted for secondary neoplasm and treatment was given to the primary neoplasm, then the primary neoplasm should be coded as primary diagnosis.

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Encounter Codes should be always coded as primary diagnosis

This is very important guidelines in ICD 10 coding. All the encounter codes should be coded as first listed or primary diagnosis followed by all the secondary diagnosis. For example, if a patient comes for chemotherapy for neoplasm, then the admit diagnosis, ROS and primary diagnosis will be coded as Z51.11, Encounter for antineoplastic chemotherapy followed by the specified neoplasm.

Read also: How to improve coding skills in Medical coding 

Coding Rule out condition as Primary diagnosis

When a patient comes with a rule out condition, and the physician confirms the presence of that condition, then it should be coded as primary diagnosis. For example, if a medical report for CTA (computer tomography angiography) Chest, 74175 has chest pain with rule out Pulmonary embolism. Now, if the physician confirms pulmonary embolism in the conclusion of the report, the primary diagnosis should be reported as pulmonary embolism.