What is the recommended workup for PTH-independent hypercalcemia secondary to an elevated 1,25-dihydroxyvitamin D level?

In the workup for PTH-independent hypercalcemia with an elevated 1,25-dihydroxyvitamin D level, what steps do you typically consider most important?

• Check serum 25-hydroxyvitamin D levels
• Evaluate for granulomatous disorders (e.g., sarcoidosis, tuberculosis)
• Screen for lymphomas
• Assess patient history for the use of vitamin D supplements, specifically 1 alpha hydroxyvitamin D3 or 1,25-dihydroxyvitamin D3
• Genetic testing for 25-hydroxyvitamin D-24 hydroxylase deficiency
• Perform imaging studies as appropriate to look for granulomas, lymphadenopathy, or other related findings
• Other