Figure 2.

Proposed diagnostic algorithm for ALK status testing in lung cancer. For example, a specimen can be tested with ALK FISH (or ALK IHC) first. If a borderline result (either borderline negative or borderline positive) is obtained, the sample will be further tested with ALK IHC (or ALK FISH). If the ALK status is still uncertain, then targeted RNA-seq is applied and the final ALK status is determined based on the NGS result. For cases with discrepant results obtained by two methods, a third methodology, if available, should be applied to clarify the discrepancy. Solid blue arrow: proposed primary test methodology or predicted test results. Solid green arrow: proposed reflex test(s). Dashed blue arrow: alternative test methodology.