The CU Index is a specialized, commercially available laboratory test designed to assess the activity of basophils, which are white blood cells involved in allergic and inflammatory responses. Specifically, it is an in vitro basophil histamine release assay primarily associated with the investigation of chronic urticaria.
Understanding the CU Index
The Chronic Urticaria (CU) Index is a diagnostic tool that measures the release of histamine from basophils. This assay provides insights into the potential involvement of autoantibodies in conditions like chronic spontaneous urticaria (CSU), where the body's immune system mistakenly attacks its own cells, leading to hives.
How the Assay Works
The CU Index operates on a principle of immunological reaction in a laboratory setting. Here's a breakdown of the process:
- Sample Collection: Patient serum, which contains antibodies and other blood components, is collected.
- Basophil Incubation: This patient serum is then mixed with donor basophils. These are basophils obtained from a healthy individual, providing a consistent cell source for the assay.
- Histamine Release: If specific autoantibodies (e.g., anti-FcεRI or anti-IgE) are present in the patient's serum, they can activate the donor basophils, triggering them to release histamine.
- Measurement: The levels of the released histamine are precisely measured through a quantitative enzyme immunoassay. The amount of histamine detected indicates the degree of basophil activation caused by the patient's serum.
This measurement can help clinicians understand the underlying mechanisms driving a patient's chronic urticaria, particularly in cases suspected to be autoimmune in nature.
Key Aspects of the CU Index
The following table summarizes the main characteristics of this diagnostic assay:
| Aspect | Description |
|---|---|
| Type of Test | In vitro basophil histamine release assay |
| Purpose | Measures histamine release from basophils activated by patient serum |
| Methodology | Patient serum combined with donor basophils; released histamine quantified via enzyme immunoassay |
| Clinical Relevance | Aids in assessing mechanisms of chronic urticaria, potentially indicating an autoimmune component. For more information on chronic urticaria, you can visit a reputable source such as the American Academy of Allergy, Asthma & Immunology. |
| Availability | Commercially available (e.g., from IBT Labs, Lenexa, KS) |
Understanding the CU Index helps in the diagnostic pathway for individuals suffering from persistent hives, guiding potential treatment strategies tailored to the underlying cause.
