The false-negative fraction: a statistical method to measure the efficacy of cervical smear screening laboratories

The false-negative fraction (FNF) is emerging as a statistical parameter that may be used to evaluate the efficacy of Papanicolaou smear screening laboratories. Our objectives for this paper are to acquaint non-laboratorians with this important measurement and to measure the FNF of the Air Force Cyto-center (AFCC) at the Armed Forces Institute of Pathology in Washington, DC. The FNF is defined as estimated false negatives divided by (true positives plus estimated false negatives). Most often, the number generated is multiplied by 100 and expressed as a percent. We have determined the FNF of the AFCC to be 3.7%. This value compares favorably with most others reported in the medical literature.