Influenza in ICD10

ICD10 Codes for Influenza

• There are 4 influenza-related codes we're using in ICD10.
• These 3 code are for actual disease due to influenza:
  • Influenza pneumonia
  • Influenza without pneumonia but with other respiratory manifestations
  • Influenza with nonrespiratory manifestations
• The 4th has a long & weird name: Influenza virus NOS -- should almost never be used
  • It is an item for the pathogen list, but as indicated it is almost never needed. This is because the other three influenza items cover virtually every influenza manifestation we can think of. We've included influenza for the pathogen list only for completeness.
• Don't confuse influenza with either of: Haemophilus influenzae (H. flu) OR Parainfluenza virus
  • See: Wikipedia for types of virus included

Identifying the Presence of Influenza

• See: Influenza tracking

We have not completely decided yet, but we are considering coding influenza as Lab-confirmed, or Suspected:

• Lab-confirmed influenza
  • Present if the final result of the testing done at Cadham was positive, and absent if not -- regardless of what the clinical team believed.
  • The tricky part here is that the hospital labs are now doing an influenza test (which is only done on swabs, not on fluid samples, and comes back quickly) PLUS they send the materials on to the Cadham lab were the testing is re-run. To further muddy the waters, Cadham gives a preliminary result which can be different than their FINAL result. On 11/21/2017 Allan spoke with the medical director at Cadham (Paul Van Caeseele) who related that the Cadham tests are more sensitive than what's done in hospitals, so that (though it's not 100% perfect) we should consider the FINAL CADHAM result to represent the truth as regards lab-confirmation of influenza.

• Suspected influenza -- here the clinical team wrote believed that it was influenza and gave a “full course” of anti-influenza drug PLUS either: (a) no lab test was sent at all, or (b) the final Cadham test result was negative.
  • For influenza that this not severe, the usual course of oseltamivir (Tamiflu) is 5 days. But WHO and CDC recommend that in severe cases the drug should be continued until the infection is resolved or there is satisfactory clinical improvement.
• We will talk about this more later, and take account of how Infection Control does this.

Alternate ICD10s to consider coding instead or in addition

• Haemophilus influenzae (H. flu)
• Parainfluenza virus