Strategic investment in healthcare infrastructure needs evidence that there are certain capabilities that have a quantifiable implication on public health. The research presented a much-needed gap in knowledge on how functional specialization of the laboratories directly affects the effectiveness of disease prevention in a national health system, with Saudi Arabia as a case study. The major goal was to measure the connection between the level of specialization of a laboratory and its performance in the detection of outbreaks, diagnostic accuracy, and reporting. A sequential design that involved mixed methods was utilized, and 62 laboratories were cross-sectionally surveyed, and 18 key informant interviews were carried out. It was found that there was a strong positive correlation between the Index of Laboratory Specialization and Prevention Effectiveness Score (r=0.924, p<0.001). Specialization was the only significant predictor of performance ( β=0.851, p<0.001) regardless of the budget or region, as found in the regression. These results indicate that improving specialization in laboratories is a high-impact, decisive measure to reinforce the national disease prevention. The findings offer a solid empirical foundation on how to optimize the laboratory network of Saudi Arabia, and also the findings give a model of how to plan an evidence-based health system in the world.