From the Guidelines
No, Calcium (Ca) Scoring (CS) testing is not appropriate as the initial workup for Primary Hyperparathyroidism (PHPT) [ 1 ].
Initial Workup
Instead, the initial workup should focus on biochemical testing, including:
- Serum calcium levels
- Serum parathyroid hormone (PTH) levels [ 1 ]
- Vitamin D levels
Additional Testing
Additional tests to consider include:
- 24-hour urinary calcium excretion test if hypercalciuria is suspected
- Comprehensive metabolic panel
- Renal function tests, including creatinine and estimated glomerular filtration rate (eGFR) [ 1 ]
Imaging Role
Imaging, such as CS testing, has no utility in confirming or excluding the diagnosis of PHPT [ 1 ]. Its role is to localize the abnormally functioning gland or glands with high accuracy and high confidence to facilitate targeted curative surgery.
Key Points
- Biochemical testing is the initial step in diagnosing PHPT
- Imaging is used to localize the affected gland, not to diagnose PHPT
- CS testing is not a recommended initial test for PHPT [ 1 ]
From the Research
Calcium Scoring Testing for Primary Hyperparathyroidism
- The provided studies do not directly address the appropriateness of ordering Calcium (Ca) Scoring (CS) testing as the initial workup for Primary Hyperparathyroidism (PHPT) 2, 3, 4, 5, 6.
- However, the studies suggest that renal function and calcifications are important considerations in PHPT patients, and that biochemical markers such as parathyroid hormone (PTH), vitamin D, and urinary calcium excretion may be useful in predicting renal calcifications and impaired renal function 2, 4, 5, 6.
- One study found that occult renal calcifications are common in patients with Normocalcemic Primary Hyperparathyroidism (NPHPT) and are associated with increased serum PTH, 1.25(OH)2D, and 24-hour urinary calcium 5.
- Another study found that renal calcifications are frequent in patients with PHPT and are associated with the severity of the disease, but impaired renal function is not associated with renal calcifications 6.
Biochemical Markers and Renal Function
- The studies suggest that biochemical markers such as PTH, vitamin D, and urinary calcium excretion may be useful in predicting renal calcifications and impaired renal function in PHPT patients 2, 3, 4, 5, 6.
- One study found that age and diastolic blood pressure were negatively associated with estimated glomerular filtration rate (eGFR), whereas serum calcium, kidney stones, and alcohol use were positive predictors of eGFR 2.
- Another study found that 24-hour urinary calcium levels were correlated with renal function and age, but these correlations are likely to occur in the general population and are not specific to PHPT 3.
Diagnostic Considerations
- The studies suggest that a comprehensive diagnostic workup for PHPT should include biochemical markers such as PTH, vitamin D, and urinary calcium excretion, as well as imaging studies to assess renal function and calcifications 4, 5, 6.
- One study found that a urine calcium to creatinine clearance ratio (CCCR) measurement below 0.020 should raise the possibility of Familial Hypocalciuric Hypercalcaemia (FHH) and genetic screening should be considered 4.