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CU Index®*

Test Code: 2103
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Clinical Utility

Patients with a chronic form of urticaria who are positive (> 10) with the CU index® have an autoimmune basis for their disease. A positive result does not indicate which autoantibody (anti-IgE, anti-FceRI or anti-FceRII) is present.


Ex-Vivo Challenge and cell culture: Donor blood cells are incubated with patient serum, a negative control and a positive control. Following the ex-vivo challenge, the cells are centrifuged and the supernatant is recovered for assay of histamine released. Histamine Analysis: Using a quantitative enzyme immunoassay, the histamine released into the supernatant is measured and compared to the total histamine in the basophils. This test has not been cleared or approved for diagnostic use by the U.S. Food and Drug Administration.

2-3 business days from receipt of specimen

Specimen Type Order Code CPT Code NY Approved Volume Assay Range Special Instructions
serum 2103 86352 No 1 mL (min. 150 uL) 1-50
  • Collect t3-5 mL whole blood in a serum separator tube (SST).
  • Centrifuge specimen within 2 hours of draw to pellet cells below the gel.
  • Patients taking calcineurin inhibitors should stop their medication for 72 hours prior to draw. Patients taking Prednisone should be off their medication for 2 week prior to draw
  • Can be shipped at ambient or frozen temperature Monday through Friday.


Specimens are approved for testing in New York only when indicated in the Specimen Information field above.

The CPT codes provided are based on Viracor Eurofins' interpretation of the American Medical Association's Current Procedural Terminology (CPT) codes and are provided for general informational purposes only. CPT coding is the sole responsibility of the billing party. Questions regarding coding should be addressed to your local Medicare carrier. Viracor Eurofins assumes no responsibility for billing errors due to reliance on the CPT codes illustrated in this material.

*Patent No.: US 7, 824, 877. Use of intellectual property owned by Viracor Eurofins to recreate, replicate or attempt in any way to determine the structure or composition of a patented or proprietary assay ("Product") is strictly prohibited and may be considered patent infringement. Further, modifying the Product, creating derivatives therof or improvements thereon, or use of Viracor Eurofins' Prodcuts and test results to evaluate, validate or certify a competing assay, may also be considered patent infringement. Please contact Viracor Eurofins' at 800-305-5198 with any questions regarding its patents, or visit for general information on patent and IP law policy.

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