Yes, Dawn, you are right. Here is an article from Coding Clinic for pneumonia that might be helpful with pna coding:
Pneumonia, unspecified
******Coding Clinic, Third Quarter 1994 Page: 10 Effective with discharges: July 1, 1994
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Question:
A patient is discharged with the diagnosis of pneumonia; however, the physician's diagnostic statement does not specify the organism. We were recently told that pneumonia not specified as viral or bacterial is assumed to be bacterial. What code should be assigned?
Answer:
Code assignment is always based on the physician's diagnostic statement. If the physician has not specified the organism then code 486, Pneumonia, unspecified, should be assigned.
All code assignments should be based upon medical record documentation, therefore, it is inappropriate to assume the presence of an organism when the documentation cannot support the code assignment. As stated in the January-February 1986 Coding Clinic and the official coding guidelines (Guideline 1.3) unspecified codes, "... are used only when neither the diagnostic statement nor a thorough review of the medical record provides adequate information to permit assignment of a more specific code." An unspecified code should be assigned when the information at hand does not permit either a more specific or "other" code assignment.
Which in summation means that pna is usually either viral or bacterial unless unspecified. Besides, if you look at code 481 - that is for pneumoccal (strep) pna, which is bacterial.
Hope some of this helps a little