List of items typical for CPPD ever present during a patient’s lifetime [7]. The highest weighted item (n) should be scored for each domain
| Domains and levels | n | |
|---|---|---|
| A | Age > 60 years at onset of joint pain, swelling, tenderness | 4 |
| B | Time-course and symptoms of inflammatory arthritis1 | |
| Persistent inflammatory arthritis 1 typical acute arthritis episode > 1 typical acute arthritis episode | 91216 | |
| C | Sites of episode(s) with peripheral arthritis and acute onset/worsening that resolves irrespective of treatment | |
| 1st MTP-joint Joint(s) other than wrist/knee/1st MTP-joint Wrist Knee | −6589 | |
| D | Related metabolic disease (hereditary hemochromatosis, primary hyperparathyroidism, hypomagnesemia, Gitelman syndrome, hypophosphatasia, or familial history of CPPD) | 6 |
| E | Synovial fluid crystal analysis from a symptomatic joint2 | |
| CPP crystals absent on 1 occasion CPP crystals absent on ≥ 2 occasions | −1−7 | |
| F | OA of hand/wrist on imaging* | |
| Bilateral radio-carpal joints ≥ 2 of the following: STT joint OA without 1st CMC joint OA; 2nd MCP joint OA; 3rd MCP joint OA | 27 | |
| G | Imaging evidence of CPPD in symptomatic peripheral joint(s)3 | |
| None on US/CT/DECT and absent on CR/CR not performed None on CR and US/CT/DECT not performed Present on either CR/US/CT/DECT | −4016 | |
| H | Number of peripheral joints with CPPD signs on any imaging regardless of symptoms | |
| 1 2−3 ≥ 4 | 162325 | |
* : osteoarthritis is defined as present if Kellgren and Lawrence score ≥ 2 [8, 9]. 1 Persistent inflammatory arthritis defined as ongoing joint swelling with pain and/or warmth. Typical episode defined as acute onset or worsening of joint pain with swelling and/or warmth that resolves irrespective of treatment; 2 synovial fluid analysis performed by individual trained in the use of compensated polarized light microscopy for crystal identification; 3 imaging of at least one symptomatic peripheral joint by CR, US, CT, or DECT required to be considered for classification if sufficient criteria are not met. Imaging evidence of CPPD refers to calcification of the fibrocartilage or hyaline cartilage. Do not score calcification of the synovial membrane, joint capsule or tendon. MTP: metatarso-phalaneal; CMC: carpo-metacarpal; CPPD: calcium pyrophosphate deposition; OA: osteoarthritis; STT: scapho-trapezio-trapezoidal; MCP: metacarpo-phalangeal; CR: conventional radiography; DECT: dual-energy computerized tomography
