Torres-Canchala L, Rengifo M, Filler G, et al. - Researchers undertook this novel cross-sectional cohort study to evaluate agreement between kidney length and kidney volume z-scores among children. From a large specialized prematurity follow-up center, prematurely born babies were prospectively observed. By age and gender, a healthy control group matched the cases. At age 5, children were examined for kidney length and kidney volumes by three independent ultrasonographers. The mean z-score of the right kidney length vs of the left kidney length was estimated to be 0.65 ± 0.08 (SEM) vs 0.88 ± 0.08. An estimate of 0.32 was obtained as the squared correlation coefficient for kidney volume to kidney length. Experts inferred that significant overestimation of age-independent z-scores happens if only kidney length is reported. In light of these observations, it may be more appropriate to consider measuring all kidney dimensions.