4-55. DIAGNOSTIC CODING (FIELDS 36 TO 43, COLUMNS 137 THROUGH 200)
a. Source of data. Item 34, ITRCS.
b. Use the ICD-9-CM, Volumes 1 and 2, to code the diagnosis(es). Coding rules
and principles are outlined in the Triservice Disease and Procedure Coding Guidelines ,
dated 1 January 1991.
c. There are eight diagnostic fields. If there are fewer than eight diagnoses
recorded on the ITRCS, leave unused fields blank. If there are more than eight
diagnoses recorded on the ITRCS, use the following priorities to select only eight:
(1) Select the principal diagnosis. The condition established by medical
examinations and tests to be the primary reason for the patient's admission is the
principal diagnosis and will be coded in field 36. When there are two or more diagnoses
of equal importance present on admission, and when the medical record documentation
does not indicate otherwise, the principal diagnosis is the one for which a definitive
surgical or nonsurgical procedure was performed. If no definitive procedure was
performed, any one of the diagnoses may be principal.
(2) Select and record complications and/or co-morbidities.
(3) Record diagnosis(es) relating to therapeutic procedures.
(4) Record the underlying cause of death or cause of disability
(5) Select etiology codes prior to manifestation codes.
(6) Select the remaining diagnoses which contributed most to prolonged
hospitalization after recording diagnoses based on the above priorities.
d. Use the first three/four/five columns in the diagnostic fields for ICD-9-CM
codes. Do not zero-fill to the fourth column for three-digit codes. Leave the fifth column
blank for four-digit codes.
e. Leave the sixth column blank. This column is reserved for future use.
f. Use the seventh column for DOD diagnostic code extenders. The codes that
require an extender are listed in Appendix A, Triservice Disease and Procedure Coding
Guidelines, dated 1 January 1991. (See Coding Principles, Appendix A of this