Diagnosis of patients with raised serum calcium level in primary care, Sweden.

Objective. To study the diagnosis of hypercalcaemic patients and to evaluate whether frequent analyses of serum calcium can detect more patients with hypercalcaemia. Design. Retrospective study of serum calcium analyses performed during the time period 1992-2000 and of the medical records of patients with elevated serum calcium levels between 1995 and 2000. Setting. Primary care in Tibro, Sweden. Subjects. Patients from the local community attending the primary healthcare centre. Main outcome measures. Frequency of serum calcium analyses, hypercalcaemic patients, and their diagnosis. Results. Doubling the number of serum calcium analyses did not increase the detected number of raised calcium levels. On the other hand, more frequent parathyroid hormone (PTH) analyses resulted in a corresponding increase in detected high PTH levels. In Tibro, 15% (n = 22) of the patients with hypercalcaemia were diagnosed with primary hyperparathyroidism, giving a rate of 0.22%. This is comparable to the prevalence in other population studies. Over 40% (n = 9) of patients with primary hyperparathyroidism in the study had only slightly raised serum calcium levels (2.55-2.60 mmol/l). In 70% (n = 99) of the cases, the cause of hypercalcaemia was unknown. The second most common diagnosis was skeletal disorders followed by kidney disease. Conclusion. An increase in the number of serum calcium analyses did not result in increased detection of raised calcium levels. In contrast, an increase in the number of PTH analyses resulted in increased detection of primary hyperparathyroidism. Therefore, PTH analyses should be used more frequently.