Identifying the presence and type of crystals in synovial fluid
Compensated Polarized Light Microscopy
Calcium Pyrophosphate Crystals
Calcium Pyrophosphate Dihydrate (CPPD)
Cholesterol Crystals
CPPD (Calcium Pyrophosphate Dihydrate)
Crystal Identification, Synovial Fluid
Gout (Urates)
Monosodium Urates (MSU)
Pseudogout (Calcium Pyrophosphate Crystals)
Pseudogout Crystals
Pyrophosphate Crystals
Synovial Fluid, Crystal Identification
Urate Crystals
Body Fluid
Question ID | Description | Answers |
---|---|---|
CRYFT | Fluid Type |
Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable: Green top (heparin)
Specimen Volume: 2 mL
0.5 mL
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Body Fluid | Refrigerated (preferred) | ||
Ambient | 24 hours | ||
Frozen |
Identifying the presence and type of crystals in synovial fluid
Birefringent crystals are found in the synovial fluid of more than 90% of patients with acutely inflamed joints.
Monosodium urate crystals are seen in gouty fluids and calcium pyrophosphate crystals are seen in chondrocalcinosis. The urates are usually needle-shaped, and the calcium crystals are often rhomboidal. Cholesterol crystals may also be observed.
None seen
If present, crystals are identified.
Positive identification of crystals provides a definitive diagnosis for joint disease.
Powdered anticoagulants such as oxalate are themselves crystalline or may cause crystals to form; their use may cause false-positive results or mask the presence of synovial fluid crystals definitive for the disease.
Hussong JW, Kjeldsberg CR, eds: Kjeldsberg's Body Fluid Analysis. ASCP Press; 2015
Synovial fluid is anticoagulated with heparin or EDTA. The specimen is examined with a polarizing microscope with and without a first-order red compensator. Cholesterol crystals appear as bright, square or rectangular plates. Pyrophosphate crystals, rhomboidal, are weakly birefringent. Urate crystals are mainly needle-shaped and strongly doubly refractile; they may be found within leukocytes.(Hussong JW, Sorensen E, Perkins SL, et al: Laboratory methods. In: Hussong JW, Kjeldsberg CR, eds. Kjeldsberg's Body Fluid Analysis. ASCP; 2015:chap 2)
Monday through Sunday
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
89060
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
CRSBF | Crystal ID, BF | 6825-4 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
CRYFT | Fluid Type | 14725-6 |
CRYID | Crystal ID | 6825-4 |
CRYCM | Comment | 77202-0 |