Internal Medicine Coding Alert

Is H1N1 presumed or confirmed? Payers want to know.

Diagnosis coding for patients who definitely have H1N1 is easy enough: You now have 488.1 to represent patients with the condition.

Problem: A patient is diagnosed with "presumed H1N1," but the internist does not order a confirmatory lab test. Should the coder use 488.1 (Influenza due to identified novel H1N1 influenza virus)?

Just because ICD-9 2010 provides a code for H1N1 doesn't mean you should automatically use it. The 2010 ICD-9-CM Official Guidelines for Coding and Reporting, effective Oct. 1, instruct you to code only confirmed cases of novel H1N1 influenza virus (H1N1 or swine flu, ICD-9 code 488.1).

"This is an exception to the hospital inpatient guidelines (Section II, H) (Uncertain Diagnosis)," states ICD-9 (www.cdc.gov/nchs/data/icd9/icdguide09.pdf).

"In this context, 'confirmation' does not require documentation of positive laboratory testing specific for avian or novel H1N1 influenza. However, coding should be based on the provider's diagnostic statement that the patient has avian or novel H1N1 (H1N1 or swine flu) influenza," reports ICD-9.

If the internist notes "suspected or possible or probable avian or novel H1N1 influenza (H1N1 or swine flu)," assign a code from the 487.x (Influenza) category, not 488.x (Influenza due to certain identified influenza viruses).

Rule: Coding should be based on the provider's diagnostic statement that the patient has novel H1N1 (H1N1 or swine flu) influenza. "In this context, 'confirmation' does not require documentation of positive laboratory testing specific for novel H1N1 influenza," according to the guidelines.

If the provider records "suspected or possible or probable novel H1N1 influenza (H1N1 or swine flu)," do not assign 488.1. Instead, you should use the appropriate influenza code from category 487.x.

"Some practices do not have the testing available, so they cannot conclude that the patient has H1N1 influenza and cannot code the condition as 488.1," says Barbara J. Cobuzzi, MBA, CPC, CENTC, CPC-H, CPC-P, CPC-I, CHCC, president of CRN Healthcare Solutions in Tinton Falls, N.J.

For instance, some physician offices in certain states are testing specimens for only influenza A and/or B and are not sending specimens to the state health department for H1N1 testing.

"In reality, to report a specific strain, one should have proof," says Philip Marcus, MD, at the St. Francis Hospital Heart Center in Roslyn, N.Y. "Otherwise, it's best to report influenza (487.x) andnot speculate."

Do this: Since influenza A and B symptoms are nearly identical to the H1N1 influenza strain, consider a diagnosis of H1N1 only when other cases have been diagnosed in the area, Marcus suggests.

"At the present time, there are no easy ways to decide which strain of influenza is responsible for an individual infection. In fact, with the recent outbreak of H1N1 infection, most of the presumed cases were indeed negative when specifically tested for H1N1 antigen," according to Marcus.