Zinc transporter 8 autoantibody (ZnT8A) by ELISA for diagnosing type 1 diabetes among Chinese people

This study aimed to evaluate the utility of enzyme-linked immunosorbent assay (ELISA) to measure ZnT8A for diagnosing type 1 diabetes among Chinese people. We recruited a group of 95 patients with type 1 diabetes, 130 patients with type 2 diabetes, and 110 subjects without diabetes. We measured ZnT8A level by ELISA and glutamic acid decarboxylase antibody (GADA) level by radioimmunoassay. We collected data on their history-based variables, body mass index (BMI), fasting blood glucose, glycosylated hemoglobin, and lipid levels. 24.2% were positive for ZnT8A in type 1 diabetics, compared to 0.0% in type 2 diabetics and 0.9% in the participants without diabetes (both p < 0.001). And the type 1 diabetics had higher ZnT8A level compared with the latter two groups (both p < 0.001). The frequency of ZnT8A in the “classical” type 1 diabetics was higher than that in patients with latent autoimmune diabetes in adults (45.0 vs. 18.7%, p < 0.05). The frequency/level of ZnT8A was higher in the youngest group (all p < 0.05). The ROC curve area was 0.892. The combination of ZnT8A and GADA increased the diagnostic sensitivity. The ZnT8A level was correlated with the GADA level. ZnT8A-positive type 1 diabetics had younger age at diagnosis (p = 0.022), lower BMI scores (p = 0.016), and more frequent ketosis (p = 0.034) and needed more insulin (p = 0.041) than ZnT8A-negative type 1 diabetics. This study demonstrated the value of ZnT8A in addition to GADA for the diagnosis of type 1 diabetes.