These lab tests are part of a standard panel used to diagnose Type 1 Diabetes.
Negative results on these tests with simultaneous diabetic indications would strongly point towards Type 2.
On the other hand, a Type 2 Diabetes diagnosis based entirely on A1c and/or a couple of BG readings would have the very real potential to be a less than accurate diagnosis.
One of the major national lab testing companies reports the following:
Positive rate in new-onset type 1 diabetes patients:
• GAD-65 antibodies = 68% positive
• ICA 512 antibodies = 72% positive
• Insulin antibodies = 55% positive
• ZnT8 antibodies = 63% positive
An increase in the number of positive antibodies is associated with a higher likelihood of type 1 diabetes.
The combined analysis has a 98% autoimmunity detection rate, with 1.8% diabetic individuals remaining as autoantibody-negative. Fewer than 3% of type 2 diabetics have positive antibodies.
“The cation efflux transporter ZnT8 (Slc30A8) is a major autoantigen in human type 1 diabetes”
https://www.ncbi.nlm.nih.gov/pubmed/17942684
The combined measurement of ZnT8A, GADA, IA2A, and IAA raised autoimmunity detection rates to 98% at disease onset…