II. Labs: Microscopy - Specific
- Monosodium Urate or MSU Crystals: Gout- Needle-shaped
- Frequently intracellular
- Strongly negatively birefringent
 
- 
                          Calcium Pyrophosphate Dihydrate (CPPD): Pseudogout- Rod or rhomboidal shaped
- Weakly positive birefringent
 
- Basic Calcium Phosphate (BCP): Calcific periarthritis- Description- Clumps and globules
- Non-birefringent
 
- Conditions- Chronic BCP Arthritis
- Milwaukee Shoulder-knee syndrome
- Mixed BCP-CPPD disease (See above)
- Osteoarthritis
- Metastatic calcinosis
 
 
- Description
- Calcium Oxalate
- 
                          Cholesterol Crystals or Lipid Microspheres- Description- Flat, rectangular plates
- Notched corners, maltese crosses
- Strongly negative birefringent
 
- Conditions- Chronic inflammatory Arthritis
- Acute Polyarthritis
 
 
- Description
- Cryoglobulin Crystals: Paraproteinemias- Polygonal Shaped
- Positively birefringent
 
III. Labs: Microscopy - Other Crystals and artifacts
- 
                          Corticosteroid Crystals: Arthritis flare post injection- Birefringent Crystals
 
- Cystine Crystals: Cystinosis
- Xanthine Crystals: Xanthinuria
- Charcot-Leyden Crystals: Hypereosinophilic Syndromes
- Aluminum phosphate: Hemodialysis
- Talc from exam gloves (Artifact)
- Apatite (Stained by Alizarin red S)
