Synovial Fluid Crystals
Urinalysis and Body
Fluids Review 520
CRYSTAL DESCRIPTION SIGNIFICANCE
Monosodium urate
Calcium pyrophosphate
Cholesterol
Gout
Pseudogout
Chronic effusions (rheumatoid arthritis)
1–30 μm long needles. Intra- or extracellular.
Strongly birefringent.
Yellow when long axis of crystal is parallel to
slow wave of red compensator; blue when
perpendicular.
1–20 μm long, 4 μm wide. Rod-shaped,
rectangular, or rhomboid.
Intracellular. Weakly birefringent. Blue when
long axis of crystal is parallel to slow wave of
red compensator; yellow when perpendicular.
Large rectangle with notched-out corner.
Extracellular.
From Strasinger SK, Di Lorenzo MS. Urinalysis and Body Fluids, 5th ed. Philadelphia: FA Davis; 2008:215.
