From Christine Fowler, New Zealand
It is Winter in the Southern Hemisphere and influenza is now
widespread. We are receiving reports of illness due to Influenza A
H3N2 and are not sure which code to assign. Should Influenza A H3N2
be
coded to J09 Influenza due to certain identified influenza virus, or
to J10 Influenza due to other identified influenza virus?
The information I have read about Influenza A H3N2 on the CDC website
states that "The virus contains genes from human, swine and avian
influenza viruses, and the M gene from the 2009 H1N1 virus" - this
would indicate that perhaps A (H3N2) should be coded to J09, however,
the Note under J09 states that "Additional virus strains may only be
included upon recommendation by WHO". Does anyone know whether or not
the WHO has made such a recommendation? Can anyone advise me of how
Influenza A H3N2 should be coded?
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Comments:
From Patricia Wood, Canada (co-Chair, Mortality Reference Group)
Hello Christine,
As you mention, additional strains of viruses causing influenza are
to
be included in J09 only on the recommendation of WHO.  I have sent a
note to Robert Jakob at WHO asking for his advice on whether or not
to
code Influenza A H3N2 to J09.  His reply will be posted as soon as it
is received.
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From Christine Fowler, New Zealand
Thank you Patricia.
I contacted the WHO Influenza group with the same query and received
the following response today from Anaïs on behalf of the WHO
Hepatitis, Influenza Respiratory Diseases and PIP framework team
(HIP);  Pandemic and Epidemic department (PED) and the Health
Security
and Environment cluster (HSE).
"For all seasonal influenza, such as H3N2, the appropriate coding is
J10. The J09 is supposed to only code for the influenza types that
are
currently not circulating in humans and therefore have a pandemic
potential."
It would be good to have this coding guideline for H3N2 confirmed by
Robert Jakob.
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From the National Casemix and Classification Centre (NCCC), Australia
This advice has been provided to Australian coders after consultation
with the WHO Family of International Classifications Network Update
and Revision Committee.
Influenza A (H3N2) update
In Australia from the period 01 July to 07 July 2012, 30% (184/615)
of
influenza like illness (ILI) samples tested were positive for
influenza. This is a two fold increase in the percent positive
recorded from the previous period (15% positive in late-June). The
majority (64%) of influenza viruses detected in Australia have been
subtype influenza A (H3N2), with the remainder being influenza B. New
South Wales, Queensland and South Australia are the states reporting
the highest numbers of positive cases. In New Zealand, ILI activity
has increased compared to previous weeks with a consultation rate of
51.9 per 100 000. This rate represents the first time in 2012 that
the
baseline of 50 ILI consultations per 100 000 population has been
reached. The ILI activity curve is mirroring the one of last year. Of
the 609 ILI samples tested from 02 July to 08 July 2012, 38% (n=235)
were positive for influenza, of these 71% (n=167) were subtype
influenza A (H3N2); the remainder were evenly mixed between influenza
A (H1N1) (pandemic 2009), unsubtyped influenza A, and influenza type
B. In the past five weeks, there has been an increasing trend of
Severe Acute Respiratory Infection (SARI) cases in New Zealand (World
Health Organization, 2012).
For more information see the WHO website
http://www.who.int/influenza/surveillance_monitoring/updates/2012__07...
Classification of Influenza A (H3N2)
To classify influenza type A (H3N2) assign the appropriate code from
category J10 Influenza due to other identified influenza virus.
J09 Influenza due to identified avian influenza virus (which is to be
renamed Influenza due to certain identified influenza virus for
ICD-10-
AM Eighth Edition) should not be assigned for influenza type A
(H3N2).
Previous advice from NCCH (2010, p. 9) instructed that this code
should only be assigned for influenza virus types A (H1N1) (swine
flu)
and (H5N1) (avian influenza) and that additional virus strains may
only be classified to this code upon recommendation from WHO. At this
time WHO has not recommended this code be assigned for influenza type
A (H3N2).
This advice is effective immediately.
References:
National Centre for Classification in Health 2010, Coding Matters:
Swine flu with pneumonia, Vol.17, No.1, p.9.
World Health Organization 2012, Influenza update No 164, accessed:
25/7/2012, available: http://www.who.int/influenza/surveillance_monitoring/updates/2012__07...

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From Patricia Wood, Canada (co-Chair, Mortality Reference Group)

Hello again, Christine!
Thank you for sharing the information you received from the WHO
Hepatitis, Influenza Respiratory Diseases and PIP framework team
(HIP);  Pandemic and Epidemic department (PED) and the Health Security
and Environment cluster (HSE).  Also useful is the information from
the National Casemix and Classification Centre (NCCC), Australia.
As it stands now, ICD-10 code J09, Influenza due to certain identified
influenza virus, includes Influenza A/H1N1 and Influenza A/H5N1.
Additional virus strains may only be included upon recommendation by
WHO.
 In the absence of such a recommendation from WHO, Influenza A/H3N2
should be coded to the appropriate subcategory of ICD-10 code J10,
Influenza due to identified influenza virus.

I hope 'flu season in New Zealand is soon over!