wPCDAI Calculator vs BoneCalc

The weighted Paediatric Crohn’s disease activity index (wPCDAI) was developed for children with Crohn’s disease to estimate disease activity based on clinical factors and common blood tests. It has been adapted from the original PCDAI. The app allows clinicians and members of the public to quickly calculate the disease activity index by answering 8 questions. The app does not store any previous calculations or patient specific information.

The BoneCalc app is designed for the calculation of Z-scores and percentiles for bone mineral content (BMC) and areal bone mineral density (aBMD) for children under 20 years of age, as measured by dual-energy X-ray absorptiometry (DXA), for the following sites: whole-body subtotal (total-body-less-head), total hip, femoral neck, lumbar spine, distal ⅓ radius and ultradistal radius. Separate race-specific (Black and non-Black) and race-neutral calculations are available by age and sex. Height-Z–adjusted Z-scores for these measures are also calculated. The BMC and aBMD data are derived from the CHOP Bone Mineral Density in Childhood Study: race-specific for ages 5–20 [Zemel B et al., J Clin Endocrinol Metab 2011;96(10):3160–3169]; race-specific for ages 1–5 [Kalkwarf HJ et al., J Clin Endocrinol Metab 2022;107(9):e3887–e3900]; and race-neutral ages 5–20 [Zemel BS et al., J Clin Endocrinol Metab 2025;110(11):3034–3048]. Calculations are also available for lumbar-spine bone mineral apparent density (BMAD) for children 5–20 years of age: race-specific [Kindler JM et al. J Clin Endocrinol Metab 2019;104(4):1283–1292] and race-neutral [Zemel BS et al., J Clin Endocrinol Metab 2025;110(11):3034–3048].