Medicaid, a program administered by individual states but involving federal funding, is the source of medical coverage for many low-income patients. This method of reimbursement is crucial for many flow cytometry laboratories, but is not well understood by many laboratory professionals. Conversely, flow cytometry often is not well understood by administrators in Medicaid offices. The potential exists for great variation in Medicaid reimbursement for flow cytometry services from state to state. As a first step toward elucidating the extent of this variation and bringing more information about Medicaid to laboratory professionals, state Medicaid offices were asked to provide the fee-for-service reimbursement for flow cytometry services. These services included Current Procedural Terminology (CPT) codes 85045 (reticulocyte counts), 86359 (total T-cell count), 86360 (absolute CD4 and CD8 counts, with ratio), 86361 (absolute CD4 count), 86812 (HLA typing, single antigen [B27]), 88180 (immunophenotyping, per surface marker), and 88182 (DNA, cell cycle analysis). Data were collected on technical and professional components and on global reimbursement. Wide variation exists in reimbursement amounts for these tests. Variation for CPT code 88180 was markedly pronounced.