The diagnosis between primary hyperparathyroidism and familial hypocalciuric hypercalcemia can be quite challenging, especially when no genetic or family information is available. To circumvent this issue, we developed the equation “Pro-FHH” that helps to predict whether a patient with parathyroid-related hypercalcemia has primary hyperparathyroidism or familial hypocalciuric hypercalcemia.
Only a few biological data (measured simultaneously) are required to perform the calculation:
- Blood calcium concentration, in mmol/L
- Parathyroid hormone concentration (and the upper limit of the normal range of the assay),
- A marker of bone formation (alkaline phosphatase or osteocalcin) with the upper limit of the normal range of the assay,
- Blood creatinine concentration, in µmol/L
- 24-h urine creatinine excretion, in mmol/d (or in mmol/L if 24-h urine calcium excretion is also expressed in mmol/L)
Download the worksheet here :
A Pro-FHH value equal to or higher than 0.928 has 100% specificity and 100% positive predictive value for the diagnosis of PHPT. By contrast, a Pro-FHH value equal to or lower than 0.061 favors the diagnosis of familial hypocalciuric hypercalcemia.
- Pro-FHH has been validated in adults only
- Pro-FHH has been validated in subjects with PTH concentration within the normal range of the assay, not yet in those with high PTH concentration
Source: J-P Bertocchio, M. Tafflet, E. Koumakis, G. Maruani, R. Vargas-Poussou, C. Silve, P. H Nissen, S. Baron, C. Prot-Bertoye, M. Courbebaisse, J-C Souberbielle, L Rejnmark, C. Cormier, P. Houillier; Pro-FHH: A Risk Equation to Facilitate the Diagnosis of Parathyroid-Related Hypercalcemia, The Journal of Clinical Endocrinology & Metabolism, Volume 103, Issue 7, 1 July 2018, Pages 2534–2542
With permission of the Endocrine Society