Urinary calcium measurement in patients with hypercalcaemia; endocrine physicians and surgeons survey results from UK

Background

In patients with hypercalcaemia, assessment of urinary calcium excretion helps differentiate primary hyperparathyroidism (PHPT) from familial hypocalciuric hypercalcaemia (FHH). For this, 24 h calcium to creatinine clearance ratio (CCCR) is recommended, but others tests like random CCCR, 24 h urine calcium excretion (UCE), and calcium to creatinine ratio (CR) are also frequently used.

Objective

The survey objective was to evaluate current practice among UK endocrinologists and surgeons.

Methods

A web-based anonymous cross-sectional survey, consisting of eight multiple-choice questions was developed using Survey Monkey. The survey was disseminated to members of British Association of Endocrine and Thyroid Surgeons (BAETS) and Society for Endocrinology (SfE) between November 20, 2025 and December 19, 2024.

Results

Two hundred and sixty-six responses from 210 endocrinologists and 56 surgeons were received (85% consultants). Respondents worked in both university (48.9%) and district hospitals (47.7%). The most commonly performed urine calcium test in hypercalcaemic patients was 24 h UCE (58.6%), but for PHPT versus FHH differentiation, the most preferred test was 24 h CCCR (43.6%), followed by random CCCR (24.8%), 24 h UCE (14.3%), and CR (16.5%). Of respondents who had experience with using CCCR (n = 235), most (55.6%) used a cut-off of > 0.01 to rule out FHH, while > 0.02 cut off was used by 26.7% respondents. Most clinicians (70.3%) used albumin-adjusted calcium for CCCR calculation, and 71.4% respondents considered vitamin D levels ≥ 50 nmol/L to be adequate for urinary calcium measurement.

Conclusion

The survey provides valuable insight into current UK practice. 24 h and random CCCR are the most commonly used tests to exclude FHH, but overall, practice varies widely.