Which investigations should be performed to confirm a diagnosis of calcium pyrophosphate deposition disease (CPPD) in a suspected case?

To confirm a diagnosis of calcium pyrophosphate deposition disease (CPPD) in a suspected case, the definitive investigation involves the identification of calcium pyrophosphate crystals [1, (Tsui, 2012)]. This is typically achieved through the microscopic examination of synovial fluid obtained from an affected joint ¹. The identification of specific crystals in synovial fluid is a cornerstone for definitively diagnosing crystal arthropathies, similar to how urate crystals confirm gout ¹,². The presence of these crystals is fundamental to understanding the mechanisms of crystal deposition in CPPD and is a key aspect in its nomenclature and classification [1, (Tsui, 2012), (Tedeschi, 2019)].