Diagnosis play a very important role in medical coding. The diagnosis codes should always fulfill the medical necessity for the procedure performed. Failed medical necessity can lead to denials. Also, the selection of principal diagnosis is very important topic in ICD coding.
There are few specific coding guidelines for choosing the primary diagnosis. There are specific ICD 10 codes which must be used as primary diagnosis only. Hence, it is very important to know about the criteria for choosing the principal or first listed diagnosis. Before we move ahead let us learn first few important ICD 10 coding tips.
Coding of Signs and Symptoms Perfectly in ICD 10
Difference Between Excludes 1 and Excludes 2 in ICD 10
Why ICD 10 codes are much better than ICD 9
ICD 10 Practice Questions with Answers
Coding Signs and Symptoms
Signs, symptoms and ill-defined conditions are included in the chapter 18 of ICD 10 codebook. As we know the signs and symptoms are always responsible or related to definitive diagnosis. Hence, whenever a definitive diagnosis related to signs & symptoms is established, it should be reported as principal diagnosis.
For example, when a patient comes with cough (R05.9) and the physician finds a pneumonia (J18.9) as establish diagnosis, then pneumonia should only be reported as principal diagnosis.
Interrelated conditions but meets the definition of principal diagnosis
There are scenarios, when two or more diagnosis meets the potential for principle diagnosis. In such a case, either of the diagnosis or condition can be coded as principal diagnosis.
For example, if a patient comes with shortness of breath, and the physician finds pneumonia(J18.9) and COPD (J44.9) as established diagnosis. In such case, any of the two conditions, pneumonia or COPD should be reported as principal diagnosis.
Similarly if two or more diagnosis that equally have the potential to meet the definition of principal diagnosis, in such case also, any diagnosis can be sequenced first.
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Coding of Uncertain Diagnosis
There are many medical reports, when the diagnosis is not at all confirmed. For example ,the use of phrases like “probable”, “suspected”, “likely”, “questionable”, “possible”, or “still to be ruled out”, along with diagnosis should not coded as confirmed diagnosis. This guideline should be strongly followed in outpatient coding.
But for inpatient admissions to short-term, acute or long-term care, the coder can code the “probable”, “suspected”, “likely”, “questionable”, “possible”, or “still to be ruled out” if the condition existed or was established. The bases for these guidelines are the diagnostic workup, arrangements for further workup or observation, and initial therapeutic approach that correspond most closely with the established diagnosis.
Coding Complications principal diagnosis
In certain scenarios, when the admission is for the treatment of a complication which has resulted from a surgery, then the complication code should be sequenced as the principal diagnosis. The complications are included in ICD 10 code series T80-T88. If there is any surgery complication then a ICD 10 code from the T80-T88 series only be reported.
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Admission from Observation Unit
When a patient is transferred from an observation unit to inpatient facility, the condition responsible for admission in inpatient facility should be reported as principal diagnosis.
Similarly, when a patient undergoes a surgery and after few days the patient develops a complication from a surgery, later the patient is admitted to inpatient facility. So, in this case the reason for admission, which is a complication, should be reported as principal or first listed diagnosis.
As per Uniform Hospital Discharge Data Set (UHDDS) definition of principal diagnosis as “that condition established after study to be chiefly responsible for occasioning the admission of the patient to the hospital for care.”
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Examples for coding Primary Diagnosis in ICD 10 as per coding guidelines
When a primary injury results in minor damage to peripheral nerves or blood vessels, the primary injury is sequenced first; then assign additional code(s) for injuries to nerves and spinal cord (such as category S04) and/or injury to blood vessels (such as category S15). When the primary injury is to the blood vessels or nerves, that injury should be sequenced first.
Malignant pleural effusion is coded to J91.0 with the underlying neoplasm assigned as the first-listed or principal diagnosis.
When treatment is directed toward the primary site, the malignancy of that site is designated as the principal diagnosis, in which case the primary malignancy is coded as the principal diagnosis, followed by any metastatic sites
