In simple words: This code is used when a lab report shows that a lung sample (biopsy or cell sample) has primary non-small cell lung cancer. The report either gives the specific type of lung cancer based on established guidelines OR says it is non-small cell lung cancer "not otherwise specified" and gives the reason why.

A pathology report for a lung specimen (biopsy, cytology) indicates a diagnosis of primary non-small cell lung cancer (NSCLC). The report provides the specific histologic type based on International Association for the Study of Lung Cancer (IASLC) guidance, or classifies the specimen as NSCLC-NOS (not otherwise specified) with an explanation.

Example 1: A patient undergoes a lung biopsy, and the pathology report identifies the presence of primary NSCLC, specifically adenocarcinoma. The pathologist uses G9418 because they documented a specific histologic type., A patient has a lung cytology performed. The report states that it is NSCLC, not otherwise specified (NOS), because the sample was insufficient for further classification. G9418 is used because there's an explanation for the NOS classification., A patient with a previous history of NSCLC undergoes a biopsy for another reason. The report mentions the prior history and confirms the current sample does not contain cancer. G9419 (not G9418) would be used here to document the reason for not classifying the current specimen.

Pathology report of lung specimen (biopsy or cytology) clearly indicating primary NSCLC, either with a specific histologic type following IASLC guidance or classified as NSCLC-NOS with a clear explanation for the NOS classification. Documentation of medical reason(s) for not classifying the specimen if applicable (e.g., insufficient sample, non-diagnostic sample, sample does not contain cancer).