Primary Care Coding Alert

ICD-9 2002 implemented a key change in asthma diagnosis coding that family physicians are still struggling with months later. Knowing the specifics of the fifth-digit code addition will help your practice receive the right reimbursement for asthma patients.

ICD-9 2002 revised the description of the fifth-digit 0 for 493 (Asthma) to read "without mention of status asthmaticus or acute exacerbation or unspecified." Previously, ICD-9 defined the 0 as "without mention of status asthmaticus." (See box at right.)

"An asthma code's fourth digit indicates whether it is extrinsic, intrinsic, chronic obstructive or unspecified, while a fifth digit indicates the degree of the asthma," says Daniel Fick, MD, director of risk management and compliance for the College of Medicine faculty practice at the University of Iowa in Iowa City. "The revision to the fifth-digit 0 clarifies that the patient's asthma is not exacerbated."

Because most patients who come into the office for asthma treatment are experiencing exacerbation, using the 0 will be more unusual than using the fifth-digit 2, Fick says. Practices usually report the 0 when a patient comes in for a checkup for his asthma.

"Now that the ICD-9 clarification includes 'without mention of acute exacerbation,' we use [the 0] less," says Donna Struve, CPC, assistant manager of the Sheldon Family Practice in Sheldon, Iowa.

Three common family practice scenarios illustrate proper fifth-digit asthma coding:

Case #1: A patient who is allergic to grass has a severe asthma attack after mowing the lawn. He goes to the emergency room (ER) extremely short of breath, and the FP is called in to treat him. The physician gives him a nebulizer and then must give an injection of epinephrine when the patient's condition worsens.

Diagnosis Coding #1: Use 493.01 (Extrinsic asthma; with status asthmaticus). The 0 after the 493 indicates that the asthma is extrinsic, meaning it was caused by an external stimulus (grass). The fifth-digit 1 indicates that the patient is in a state of status asthmaticus. FPs rarely encounter patients with status asthmaticus because it is a severe state usually requiring hospitalization, Fick says. However, particularly in rural areas, the patient's regular FP may be called to the ER to treat the patient.

Case #2: A patient who regularly uses an inhaler complains to the FP that the inhaler is not relieving her asthma. The physician performs a peak-flow test, which measures 200 l/m instead of the normal 400 l/m. The FP increases the patient's therapy.

Diagnosis Coding #2: Report 493.12 (Intrinsic asthma; with acute exacerbation). The fourth-digit 1 shows that the asthma is intrinsic, while the fifth-digit 2 indicates that the patient had an acute exacerbation. "The most common visits for asthma patients are due to acute exacerbation of the reactive airway disease," Fick says.

Case #3: A patient with mild intrinsic asthma comes in to have the condition checked annually. The FP performs a routine check and determines the asthma is well controlled.

Diagnosis Coding #3: Use 493.10 (Intrinsic asthma; without mention of status asthmaticus or acute exacerbation or unspecified). In this case, using the fifth-digit 0 is appropriate because the asthma is under control and absent of status asthmaticus or acute exacerbation. "Before the clarification, the 0 also would have been used because it is a default in this situation. Neither the 1 nor the 2 is appropriate," Struve says. The same coding applies if the FP determined a patient's asthma to be stabilized during a follow-up visit, after an initial visit to treat exacerbated asthma.