Clinical distinction of type 1 from type 2 diabetes mellitus
Identification of individuals at risk of type 1 diabetes (including high-risk relatives of patients with diabetes)
Prediction of future need for insulin treatment in adult-onset diabetic patients
Radioimmunoassay (RIA)
Anti-IA2 Antibodies
ICA-512
Islet Cell Antibody
Serum
Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Specimen Volume: 1.5 mL
1 mL
Gross hemolysis | Reject |
Gross lipemia | Reject |
Gross icterus | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 28 days | |
Frozen | 28 days | ||
Ambient | 72 hours |
Clinical distinction of type 1 from type 2 diabetes mellitus
Identification of individuals at risk of type 1 diabetes (including high-risk relatives of patients with diabetes)
Prediction of future need for insulin treatment in adult-onset diabetic patients
Islet cell autoantibodies have been known to be associated with type 1 diabetes mellitus for many years. In recent years, several autoantigens against which islet antibodies are directed have been identified. These include the tyrosine phosphatase-related islet antigen 2 (IA-2), glutamic acid decarboxylase 65, zinc transporter 8, and insulin. One or more of these autoantibodies are detected in 96% of patients with type 1 diabetes and are detectable before clinical onset, as well as in symptomatic individuals. A serological study of 50 individuals with type 1 diabetes and 50 control subjects conducted simultaneously across 43 laboratories in 16 countries demonstrated a median sensitivity of 57% and a median specificity of 99% for IA-2 antibody in type 1 diabetes. Prospective studies in relatives of patients with type 1 diabetes have shown that development of 1 or more islet autoantibodies (including IA-2 antibody) provides an early marker of progression to type 1 diabetes. Autoantibody profiles identifying patients destined to develop type 1 diabetes are usually detectable before age 3. In one study of relatives seropositive for IA-2 antibody, the risk of developing type 1 diabetes within 5 years was 65.3%. Some patients with type 1 diabetes are initially diagnosed as having type 2 diabetes because of symptom onset in adulthood, societal obesity, and initial insulin-independence. These patients with "latent autoimmune diabetes in adulthood" may be distinguished from those patients with type 2 diabetes by detection of 1 or more islet autoantibodies (including IA-2).
< or =0.02 nmol/L
Reference values apply to all ages.
Seropositivity for islet antigen 2 autoantibody (> 0.02 nmol/L) is supportive of:
-A diagnosis of type 1 diabetes
-A high risk for future development of diabetes
-A current or future need for insulin therapy in patients with diabetes
Negative results do not exclude the diagnosis of or future risk for type 1 diabetes mellitus. The risk of developing type 1 diabetes may be stratified further by testing for antibodies targeting insulin, glutamic acid decarboxylase, and zinc transporter 8 (ZnT8) and human leukocyte antigen genetic markers. Careful monitoring of hyperglycemia is the mainstay of determining the requirement for insulin therapy.
1. Shields BM, Shepherd M, Hudson M, et al; UNITED study team: Population-based assessment of a biomarker-based screening pathway to aid diagnosis of monogenic diabetes in young-onset patients. et al: Diabetes Care. 2017 Aug;40(8):1017-1025. doi: 10.2337/dc17-0224
2. Bingley PJ: Clinical applications of diabetes antibody testing. J Clin Endocrinol Metab. 2010 Jan;95(1):25-33
3. Bingley PJ, Bonifacio E, Mueller PW: Diabetes Antibody Standardization Program: first assay proficiency evaluation. Diabetes 2003 May;52(5):1128-1136
4. Christie MR, Roll U, Payton MA, et al: Validity of screening for individuals at risk for type I diabetes by combined analysis of antibodies to recombinant proteins. Diabetes Care. 1997 Jun;20(6):965-970
5. Lampasona V, Petrone A, Tiberti C, et al: Zinc transporter 8 antibodies complement GAD and IA-2 antibodies in the identification and characterization of adult-onset autoimmune diabetes: Non Insulin Requiring Autoimmune Diabetes (NIRAD) 4. Diabetes Care. 2010 Jan;33(1):104-108
Iodine-125 ([125]I)-labeled recombinant human islet cell antigen (IA-2) is added to the test serum; if antibody is present, it forms a soluble complex with the (125)I-labeled IA-2. Subsequent addition of goat antihuman IgG precipitates the complex. The amount of radioactivity in the precipitate is proportional to the level of antibody in the serum.(Unpublished Mayo method)
Monday through Friday
This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.
86341
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
IA2 | IA-2 Ab, S | 81155-4 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
89588 | IA-2 Ab, S | 81155-4 |
Change Type | Effective Date |
---|---|
Test Status - Test Resumed | 2021-08-04 |
Test Status - Test Delay | 2021-07-22 |