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Data Element Name:  Principal/Primary Diagnosis Code File Location:   Master, De-Identified, De-Identified Abbreviated
SPARCS Data Element Number:  68
Record Positions:  1327 - 1332 Format-Length:  A/N - 6
Effective Date:  1/1/1994 Revision Date:  January 1997
Deniable Data Element:  No


The Principal/Primary Diagnosis is the condition established after study to have been chiefly responsible for occasioning the admission of the patient to the hospital for care. Since the Principal/Primary Diagnosis represents the reason for the patient's stay, it may not necessarily have been the diagnosis which represented the greatest length of stay, the greatest consumption of hospital resources, or the most life-threatening condition. Since the Principal/Primary Diagnosis reflects clinical findings discovered during the patient's stay, it may differ from Admitting Diagnosis.

Codes and Values:
  1. Must have been a valid ICD-9-CM code excluding decimal points. To have been valid, ICD-9-CM codes must have been entered at the most specific level to which they are classified in the ICD-9-CM Tabular List. Three-digit codes further divided at the four-digit level must have been entered using all four digits. Four-digit codes further subclassified at the five-digit level must have been entered using all five digits. Failure to enter all required digits in the diagnosis codes would have caused the record to be rejected.

  2. Must have been left justified and entered exactly as shown in the ICD-9-CM coding reference, excluding the decimal point, and space filled.

  3. Manifestation and Unacceptable Principal/Primary Diagnosis conditions as indicated by the edit flag on the ICD-9-CM reference file were invalid.

  4. E-codes were not valid as Principal/Primary Diagnosis Codes. E-codes are reported in External Cause-of-Injury Code (Data Element 77) and Place-of-Injury Code (Data Element 78).
Edit Applications:
  1. Edits pertaining to ICD-9-CM codes are validated on the basis of the Discharge Date (Data Element 6 & 7) and Expected Principal Reimbursement (Data Element 28) depending on conditions described in Appendix N, which includes age-specific and sex-specific diagnosis code conditions.

  2. When the edit flag on the ICD-9-CM reference file indicates an "unacceptable principal/primary diagnosis without a secondary diagnosis" an Other Diagnosis Code 1-14 (Data Element 69) must have been reported.

  3. Diagnosis codes reported in the range of 800.00-999.99 required the reporting of a valid External Cause-of-Injury Code (Data Element 77) unless as an exception in Appendix N.

  4. If the Neonate Birth Weight (Data Element 21) was reported as less than 1500 grams, and the New York State Patient Status (Data Element 22) was reported as code "01" home, then the Length of Stay must have been greater than 10 days.