Cryoglobulin Screen with Reflex to Cryoglobulin Panel [37358]

For Specimen Integrity during Extreme Weather see the “Lockbox Usage in Extreme Weather” document at the top of this page.

Test Code

Alias/See Also

CPT Codes

If cryoglobulin is present (positive), it is identified. Positives are semi-quantitated (as % cryoglobulin) by cryocrit.
When Cryoglobulin Screen is positive, Cryoglobulin Panel (Cryocrit Immunofixation, Cryocrit Immunodiffusion and Rheumatoid Factor) will be performed at an additional charge (CPT Code(s): 86334, 86329, 86431).

Preferred Specimen
10 mL serum collected in a red-top tube (no gel)

Patient Preparation
Overnight fasting is required.

Minimum Volume
3.5 mL

Stability restrictions: Sample has only 72 hr stability.  Only draw Mondy through Thursday.

Collect 20 mL of fasting whole blood specimen in a red-top tube (no gel). 10 mL serum required: 3.5 mL minimum. Avoid hemolysis. -Allow serum sample to clot for one (1) hour in a 37°C water bath, oven, incubator, or heat block. -After clotting, centrifuge the specimen for 10 minutes at 3000 rpm utilizing one of the 3 options below: 1) In a "warm" centrifuge at 37° C; or 2) In a bench-top centrifuge placed in a "warm room" at 37°C; or 3) At room temperature, in a bench-top centrifuge prewarmed by running it for 10 minutes at 2000 rpm. -After centrifuging, decant serum into a screw-capped vial -Transport at room temperature. Note: No other tests can be added to the tube; cryocrit and cryoglobulin evaluation only

Transport Container
Plastic screw-cap vial

Transport Temperature
Room temperature

Specimen Stability
Room temperature: 72 hours
Refrigerated: Unacceptable
Frozen: Unacceptable

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis • Lipemia • Icteric • Serum separator tube (SST)

Cryocrit • Electrophoresis • Immunodiffusion (ID) • Immunofixation (if needed) • Rate Nephelometry

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the U.S. Food and Drug Administration. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule
Set up: Sun-Fri; Report available: 6-8 days

Reference Range
Cryoglobulin, QL Negative in normal individuals

Clinical Significance
Cryoglobulins are proteins that precipitate from serum at temperatures below 37° C. Most precipitate when serum is cooled at 4° C, but some gel even at room temperature. The gel or precipitate must redissolve at 37° C to be classified as a cryoglobulin.

Performing Laboratory
Quest Diagnostics Nichols Institute-San Juan Capistrano, CA
33608 Ortega Highway
San Juan Capistrano, CA 92675-2042

Last Updated: November 29, 2021

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.