Flow Cytometry, Ektacytometry, DNA Ploidy, and S-phase Fraction

Flow cytometry for cell-surface marker analysis is covered when needed to evaluate abnormal tissue, bone marrow, or blood suspicious for lymphoma, leukemia, or myelodysplastic syndrome, and for B‑cell monitoring in immunosuppressive disorders, hairy cell monitoring, hereditary persistence of fetal hemoglobin, and hereditary spherocytosis; however, flow cytometry–derived DNA ploidy or S‑phase testing is not indicated for routine prognostic/therapeutic use and is considered investigational for many solid tumors (e.g., breast, cervical, colorectal, non–small cell and small cell lung cancer, pediatric intracranial tumors), and RBC adhesion index testing (CPT 0303U/0304U) is investigational and not covered. Ploidy/S‑phase testing is generally limited to a single test per tumor lifetime, usually performed after diagnosis and before treatment, and may be considered medically necessary only for listed localized cancers when prognostic information will affect treatment decisions.