Endocrine Abstracts

Type 1 diabetes (T1D) is diagnosed in the appropriate clinical context with diabetes-specific autoantibodies (DSAABs). Consensus guidelines on diagnosing T1D advise a cascade testing approach: if glutamic acid decarboxylase (GAD) are negative, it should be followed by paired islet tyrosine phosphatase 2 (IA2) and zinc transporter 8 (ZNT8). This audit evaluated at the use and cost of DSAABs in new T1D presentations in SVUH. We reviewed clinical files and laboratory testing for the last 100 people newly diagnosed with T1D in the outpatient setting. Costs were based on retail price from the laboratory (GAD C=25, ZNT 8 C=88.88, IA 2 C=38.88, insulin antibodies [INSAB] C=35.33 and islet cell antibodies [ICA] C=40). We examined the cost savings of cascade testing. Of the 100 people audited, 42% were female. Median age was 36 years (interquartile range[IQR]=18). All had GAD tested, 88% were positive. Of these 81% (n = 71) had other DSAABs ordered (ZNT8=40, IA 2=39, ICA=60, INSAB=31). Of the 12 GAD negative patients, 10 underwent further antibody testing (ZNT8=7, IA 2=4, ICA=9, INSAB=8). For these 100 patients, the total cost of antibody testing was C=11,066.75 (GAD=C=2,500, ZNT 8=C=3,555.20, IA 2=C=1,516.32, ICA=C=2,400, INSAB=C=1,095.23). If cascade testing was used, the total cost would have been C=4,033.12, resulting in a cost saving of C=7,033 or C=70.33 per patient (GAD=C=2,500, IA 2=C=466.56, ZNT 8=C=1,066.56). This audit shows that improvements in testing efficiency and cost savings of potentially up to 60% could be achieved if a protocol-based testing cascade following consensus recommendations was implemented.