Pathology/Lab Coding Alert

Question: Our lab received an order for a strep test for a patient with “recent onset sore throat” to “rule out strep.” What ICD-10 code should we use?

Codify Subscriber

Answer: You should bill the ordering diagnosis as J02.9 (Acute pharyngitis, unspecified).

You should never code a “rule out” condition as though it exists, so you should not code the case as J02.0 (Streptococcal pharyngitis). Nor do you have results indicating that another specific organism is the cause, so you should not bill with J02.8 (Acute pharyngitis due to other specified organisms).

Because the physician specifies “recent onset,” you know that the sore throat is not chronic, so you would not select J31.2 (Chronic pharyngitis).

Bottom line: As a lab coder, you should bill a test using the ordering diagnosis. If the physician provides only a narrative diagnosis, and not the ICD-10 code, then you’ll have to select the most appropriate code as in this example.