2. Methodology
This research proposed a NDEA model in a four-stage network that consists of three main laboratory processes (pre-testing, testing and post-test), which is unprecedented in the field of health care thus far. Also due to the importance of undesirable inputs and outputs in healthcare sectors, in the proposed model undesirable data is considered. Then, a real case study of diagnostic laboratories in Iran is given to demonstrate the effectiveness of the model. The benefits of the proposed approach show that efficiency scores can help administrators manage their deficiencies and ultimately improve their business.