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Universal screening of all new colorectal cancers using mismatch repair (MMR) immunohistochemistry and/or microsatellite instability (MSI) testing identifies patients with possible Lynch syndrome and those with dMMR/MSI-H tumors that have prognostic and therapeutic significance. Absent or weak IHC staining (MLH1, MSH2, MSH6, PMS2) or MSI-H prompts further evaluation: MLH1 loss often requires BRAF or MLH1 promoter methylation testing to distinguish sporadic from hereditary; if hereditary is suspected, refer for germline testing/counseling. dMMR/MSI-H tumors may benefit from immune checkpoint inhibitors in advanced disease and have different adjuvant considerations. Limiting germline testing to family history (Option A) misses many carriers. KRAS alone (Option C) guides anti-EGFR therapy but not Lynch risk. Waiting until recurrence (Option D) delays critical familial risk reduction and potential treatment choices. The APRN coordinates pathology, genetics referral, informs relatives about cascade testing, and documents results in survivorship plans for ongoing care.