CPT® Code 85461

The CPT® Code 85461 refers to a laboratory test specifically designed to measure fetal hemoglobin or red blood cells (RBCs) in maternal blood, particularly in the context of fetomaternal hemorrhage (FMH). This test serves as a qualitative screening tool that is typically ordered when there is a suspicion of a larger than expected FMH, which can occur during pregnancy or delivery. The mixing of fetal blood with maternal blood can have significant implications, especially for Rh-negative women carrying an Rh-positive fetus. In such cases, the transfer of fetal cells into the maternal circulation may lead to maternal Rh immunization, posing risks for future pregnancies. A positive result from this qualitative screening test necessitates further investigation through a quantitative test, specifically CPT® Code 85460, to accurately determine the appropriate dosage of Rh immune globulin (RhoGAM) that should be administered to the mother either postpartum or after a preterm fetal loss. The test is conducted by obtaining a blood sample through a venipuncture, which is a separately reportable procedure, and the analysis is performed on whole blood using a technique known as red blood cell rosetting.