R is the ratio of standard deviations for groups of body mass index. DU/L is the absolute difference in upper or lower reference limits between groups of body mass index, divided by the smaller of the two standard deviations. Partitioning is justified statistically where R>1.5, or DU/L is ≥0.75. Partitioning may be considered where DU/L is ≥0.25 but <0.75. A common reference interval for CRP should be used where DU/L is <0.25.17