Lab workup for newly diagnosed CPPD
Appropriate laboratory workup in a patient with newly diagnosed CPPD
Most cases of CPPD are sporadic or associated with normal aging. If the CPPD is severe or affects many joints, or the patient is younger than 50 years, it is reasonable to search for a metabolic cause. Evaluations must be individualized for persons older than 55 years, with hyperparathyroidism being a primary consideration. Recommended laboratory studies include:
• Calcium (rule out hyperparathyroidism).
• Phosphorus.
• Magnesium (rule out hypomagnesemia, usually from renal wasting—Gitelman’s syndrome).
• ALP (rule out hypophosphatasia).
• Ferritin, iron, total iron-binding capacity (rule out hemochromatosis).
• Renal function.