Diabetes Autoantibody Standardization Program (DASP)
DASP is a collaboration of the IDS and the Centers for Disease Control and Prevention (CDC) to improve the sensitivity, specificity and comparability of the measurement of autoantibodies associated with type 1diabetes. DASP is built upon the foundation of previous IDS Workshops that demonstrated marked variability between laboratories in the sensitivity and specificity of assays for autoantibodies to GAD65, IA-2A, and insulin.
The first DASP Proficiency Testing (PT) evaluation in the fall of 2000 showed that radiobinding assays for GADA and IA-2A generally achieve high sensitivity and specificity, and that inter-laboratory concordance is good when samples are ranked, or if results are expressed in common units based on the WHO reference reagent. It did however indicate that that problems persist in the measurement of autoantibodies to insulin. Some IAA microassays have high levels of sensitivity and specificity with good concordance among laboratories, but the sensitivity of assays in most laboratories is low.
The Program is implementing a number of activities to address these issues.
1) A full analysis of each laboratorys assay characteristics compared to other laboratories has been carried out and circulated to participating laboratories.
2) Insulin Autoantibody (IAA) Optimization Sets have been circulated to participating laboratories to allow them to evaluate, prior to the next full workshop, the changes they have made to improve assay sensitivity and specificity.
3) Sets of sera from 250 healthy controls are being assembled to aid laboratories in defining comparable cut-offs. These will be available to DASP laboratories wishing to assay a common set of control samples in addition to their own normal populations.
4) Laboratories that met a set of criteria based on performance in DASP 2000 will be designated to provide details of assay methods, and to offer training. They will also be involved in the characterization of DASP sample sets made available for the evaluation of novel markers and assay technologies. These laboratories will also provide a focus for collection of additional samples for DASP sets.
5) The next DASP proficiency testing evaluation will take place early in 2002. To register for this, please download the registration form or contact . Registrations close on April 1, 2002.