From the Research
The evaluation of hypercalcemia should begin with confirming the elevated calcium level through repeat testing of total serum calcium and albumin, or measuring ionized calcium directly, as recommended by recent studies 1, 2. The initial step in evaluating hypercalcemia is to confirm the elevated calcium level. This can be done by repeating the test for total serum calcium and albumin or by measuring ionized calcium directly. Initial laboratory studies should include:
- Parathyroid hormone (PTH)
- Phosphorus
- 25-hydroxyvitamin D
- 1,25-dihydroxyvitamin D
- Renal function tests (BUN, creatinine) Additional tests may include:
- PTH-related protein (PTHrP)
- Serum and urine protein electrophoresis
- Thyroid function tests
- 24-hour urine calcium Imaging studies should be tailored to the suspected cause, such as:
- Neck ultrasound or sestamibi scan for suspected hyperparathyroidism
- Chest X-ray to screen for malignancy or granulomatous disease
- Skeletal survey or bone scan if multiple myeloma or metastatic disease is suspected
- CT scans of the chest, abdomen, and pelvis may be necessary to identify occult malignancies, as suggested by 2. These tests help distinguish between PTH-dependent causes (like primary hyperparathyroidism) and PTH-independent causes (such as malignancy, granulomatous disorders, or medication effects), allowing for appropriate treatment planning, as discussed in 3, 4, 5, 1. The urgency and extent of evaluation depend on the severity of hypercalcemia, with severe elevations (>14 mg/dL) requiring more immediate and comprehensive assessment, as indicated by 1.