A model to estimate spleen volume from palpated spleen length in patients with myelofibrosis.

Spleen volume is commonly assessed in clinical trials involving patients with myelofibrosis (MF), but direct measurement requires radiologic imaging. In routine clinical settings, spleen length measured by palpation is frequently used as an alternative measure. As the relationship between spleen length and spleen volume is not strictly proportional, interpretation of palpation-based measurements may be variable. In this post hoc analysis, we examined the relationship between palpable spleen length and spleen volume in patients with MF using pooled data from two phase 3 clinical studies. Palpable spleen length and patient weight, height, age, and sex were evaluated using mixed-model regression to identify variables associated with spleen volume. A regression model incorporating palpable spleen length and patient height provided the best fit for predicting spleen volume. The model presented here defines a quantitative relationship between palpable spleen length and spleen volume and provides a standardized reference for relating these measurements in research and observational contexts.