Islet cell antibody titer

Category: Endocrinology and Infertility
Test Code: 215
Disease: Type 1 Diabetes (IDDM)
Methodology: Indirect Immunofluorescence
Substrate: Primate Pancreas
Reference Range: Negative: <1:5
Units: Titer
Note: Positive samples at a 1:5 screening dilution are titered to an endpoint at an additional charge.
CPT Code: 86341
Schedule / Turnaround Time: Assay performed once weekly. Report availability is within one week from the time of specimen receipt.
Specimen Requirements:

Specimen need not be refrigerated or frozen. Collect 2-3 ml of blood in a red top or serum separator tube. If possible, separate serum from clot and place into white tube provided with Immco Diagnostics’ collection kits. If separation facilities are not available, the blood can be sent in the tube used for collection.

Sample Stability:

Sample is stable at ambient temperature during shipment. If sample is stored prior to shipment, it is stable refrigerated (2-8˚C) up to five days and frozen (-20˚C or lower) up to one year.


Most cases of diabetes fall into two clinical categories: insulin dependent diabetes mellitus (IDDM or Type I diabetes) and non-insulin dependent diabetes mellitus (NIDDM or Type II diabetes). Prognosis, treatment and disease management are different for each type. It is well accepted that Type I diabetes is an autoimmune disease targeting ß-cells of the islets of Langerhans in the pancreas. The autoimmune response to islet cell antigens elicits antibody responses to antigens such as glutamic acid decarboxylase (GAD), ICA-512 and insulin. They have been found to be highly predictive markers, particularly if present in high titer. Detection of these ICAbs by indirect immunofluorescence on pancreas substrate is considered the gold standard for diagnosis of Type I dibabetes. These cytoplasmic ICAbs are currently used for the prediction of Type I diabetes. ICAbs are detected in up to 90% of newly diagnosed diabetic patients. The level of ICAbs appears to be highest prior to the onset of Type I diabetes and diminishes progressively thereafter.