Medical laboratory turnaround time (TAT) is the total time consumed by the medical laboratory to complete a testing cycle and make the result available. Turnaround time is determined by 3 main stages: the preanalytical, analytical, and postanalytical times. The goal of this work is to analyze and reduce TAT in developing countries as a complete process starting from when the sample was drawn until delivery of the result to the requesting physician. This study covered healthcare facilities in Egypt as a sample of developing countries. A dynamic system simulation model was used in this work. This model was designed to reduce TAT by studying the 8 most critical parameters that affect TAT. A causal loop diagram was developed using real laboratory data collected from 15 different hospitals in Egypt. The 8 key parameters are number of samples, number of equipment, total staff count, staff performance, environmental conditions, preanalytical and postanalytical time, equipment defect increase rate, and number of rack samples. The results showed that TAT is directly proportional with number of samples, preanalytical and postanalytical time, and equipment defects. The results also showed that TAT is inversely proportional with the other key parameters. This study highlights the need for continuous improvement and focuses on the environment surrounding the analysis process in a medical laboratory where TAT was reduced by about 70% and patient satisfaction increased, which are less costly and an applicable solutions in developing countries.