What is a key benefit of multicenter reference intervals compared to single-lab RI?

• A. Wider confidence intervals
• B. Narrower 90% CI
• C. Increased cost
• D. Less generalizable

Answer: (B)

Pooling data from multiple centers improves the precision and generalizability of reference intervals. A single laboratory RI can reflect local factors—specific patient mix, instrumentation, and assay calibration—leading to greater sampling error in estimating the true population limits. By contrast, multicenter RI brings together data from diverse populations and methods, increasing the total sample size and reducing center-specific biases. This broader, more representative dataset yields narrower uncertainty around the estimated lower and upper reference limits, so the 90% confidence interval around those limits tightens. That improved precision is the key benefit, making the RI more reliable when applied to the wider patient population. The other choices describe outcomes opposite to this benefit or practical drawbacks rather than advantages: wider confidence intervals indicate less precision, higher cost is a potential drawback rather than a benefit, and being less generalizable would undermine applicability.