What is it called when the reference population is subdivided into subgroups based on physiologic differences expected to cause clinically important differences in RI?

• A. Partitioning
• B. Stratification
• C. Segmentation
• D. Calibration

Answer: (A)

Dividing a reference population into subgroups that differ physiologically so that each subgroup has its own reference interval is partitioning. This approach recognizes that factors like age, sex, breed, or other physiological differences can shift what’s considered normal, so each subgroup gets its own range rather than a single pooled one. That way, a patient is compared to the most appropriate reference, reducing misclassification of normal or abnormal results. While stratification can describe dividing into groups in study design, partitioning is the term most used when establishing subgroup-specific reference intervals. Segmentation isn’t the standard term for this process, and calibration relates to aligning measurement values to a standard, not population subdivision.