Crystal ID, body fluid

Alphabetical Test listing

Crystal ID, body fluid-425

Crystal ID, body fluid

To differentiate gout (sodium urate crystals) from pseudogout (calcium pyrophosphate crystals). These crystals are detected by polarized light microscopy with the addition of a first order red compensator that alters the passage of light into slow and fast components. The line on the compensator shows the vibration direction of the slower component. Sodium urates can be present in gout. The calcium pyrophosphates can be present in pseudogout.


Body fluid
2.0 mL
0.5 mL

Submit entire specimen


Lavender (EDTA), 4mL

A sample with no preservative is preferred for the crystal ID, however, if both a cell count and crystal ID is ordered and there is not enough sample, both tests can be performed off of an EDTA tube. 

  • Source

Refrigerated (strict) - 48 hrs

  • Improper label (unlabeled or mislabeled)
  • Clotted specimen
  • Delay in transport
  • Improper storage/transport temperature
AHL - Hematology: H
1 day

Polarized microscopic examination


No crystals seen