Internal Medicine Coding Alert

Hint: You cannot use the same code when the diagnosis is mixed anxiety disorder.

When your internist diagnoses a patient with generalized anxiety disorder, you report the diagnosis in the same way as you did in ICD-9. You have a one-to-one transition code for the disorder in ICD-10, but you need to be aware of other code choices that you will have to use when anxiety is associated with other conditions.

ICD-9: When your clinician diagnoses generalized anxiety disorder, you’ll have to report the diagnosis with 300.02 (Generalized anxiety disorder). In ICD-9, you report a diagnosis of mixed anxiety disorders using 300.09 (Other anxiety states).

You cannot use 300.02 when your clinician diagnoses the patient with anxiety in acute stress reaction (308.0) or transient adjustment reaction (309.24).

You also cannot use 300.02 when your clinician diagnoses the patient with separation anxiety (309.21); neurasthenia (300.5) or psychophysiological disorders (306.0-306.9).

ICD-10: When you switch over to using ICD-10 codes for reporting your clinician’s diagnoses, a diagnosis of generalized anxiety disorder that you report with 300.02 in ICD-9 crosswalks to F41.1 (Generalized anxiety disorder). You can use F41.1 if your physician’s diagnosis is also anxiety neurosis, anxiety reaction, anxiety state, or overanxious disorder. If the diagnosis is mixed anxiety disorders, you will have to report this with F41.3 (Other mixed anxiety disorders) instead of F41.1.

Caveat: As in ICD-9, you cannot use F41.1 for a diagnosis of neurasthenia. You report this diagnosis with F48.8.

Focus on These Basics Briefly

Documentation spotlight: Your physician will arrive at a diagnosis of a generalized anxiety disorder based on a complete history and a complete evaluation of the patient. Your doctor will perform a complete mental status examination, a complete psychiatric and medical history of the patient and family, and a review of systems.

Some of the findings that your clinician would most likely record in a patient with generalized anxiety disorder will include trouble sleeping, palpitations, getting tired easily, irritability, restlessness, and having issues with concentration.

Upon examination, your clinician might note shortness of breath, tachycardia, clammy extremities, nausea, dizziness, headache, increased sweating, and dryness of the mouth.

If your provider suspects a diagnosis of generalized anxiety disorder, he might also want to rule out other conditions, such as depression, and other anxiety disorders, like anxiety states due to substance or drug abuse and sexual dysfunction. 

Tests: Although there are no specific diagnostic tests available for your clinician to clinch a diagnosis of generalized anxiety disorder, he might still perform or order some tests to rule out other conditions that might present with similar symptoms and findings.  

Some of the tests that your clinician is more likely to order in a patient in whom your clinician suspects anxiety disorder will include complete blood count (CBC), arterial blood gases (ABG), thyroid function tests, and tests to check for drug or other substance abuse. He might also order an EEG if he suspects other neurologic conditions or order an ECG to rule out cardiac conditions.