CPT code 85306 describes a laboratory assay performed by a lab analyst to measure free protein S levels in a patient’s plasma; the service is a specialized coagulation protein test typically performed in a clinical laboratory or hospital lab setting for evaluation of coagulation disorders or thrombophilia.

For related coverage guidance, see recent payer policy updates: Epithelial Cell Cytology in Breast Cancer Risk Assessment, Antibody-Drug Conjugates, Chemotherapy Observation or Inpatient Hospitalization (for New Mexico Only).