Frequently Asked Questions

ADAP (Antibody Detection by Agglutination-PCR) is an advanced immunoassay technology developed by Enable Biosciences. It uses PCR to detect disease-related autoantibodies with enhanced analytical sensitivity, aiding in the early detection of type 1 diabetes (T1D) autoantibodies.

The ADAP test screens for three primary T1D-associated antibodies: anti-GAD65, anti-IA2, and anti-Insulin.

Validation studies with serum samples reported a positive predictive value (PPV) of 68% and a negative predictive value (NPV) of 92%, based on findings from the Diabetes Prevention Trial for Type 1 Diabetes. In comparison, a radiobinding assay demonstrated a PPV of 67% and an NPV of only 66%—26% lower than ADAP's performance. Predictive values may vary when using dried blood spot samples.

In the validation study for dried blood spot samples, the ADAP assay demonstrated greater than 95% sensitivity, with 20 out of 20 true positives correctly identified ("detected"). It also showed 97% specificity, with 33 out of 34 true negatives correctly classified as "not detected." This translates to a false-negative rate of less than 5% and a false-positive rate of 3%.

ADAP testing shows a strong correlation between serum and dried blood spot samples collected simultaneously from the same individuals, with an R-value of 0.97.

ADAP is exceptionally sensitive and specific, frequently matching or surpassing traditional methods such as radiobinding and ELISA in accuracy. It also detects very low levels of T1D autoantibodies, which may be beneficial for early diagnosis.

The ADAP test is certified as a Laboratory Developed Test (LDT) under CLIA and CAP guidelines, but it has not been reviewed by the FDA.

ADAP's high sensitivity and specificity make it ideal for large-scale population screening. Studies demonstrate that it performs comparably to, or better than, standard T1D screening assays in terms of diagnostic accuracy.

For further information or technical support, please email Enable Biosciences at clinical@enablebiosciences.com.

The Islet Autoantibody Standardization Program (IASP) is a global initiative designed to improve and standardize the detection of islet autoantibodies, which are key markers for type 1 diabetes. By organizing regular workshops, IASP evaluates the performance of different laboratories and testing methods to ensure accuracy, reliability, and comparability in autoantibody detection. This effort supports advancements in research, diagnosis, and prevention of type 1 diabetes.

While only partial data from each IASP is published, Enable's laboratory performance can be shared upon request.

Islet Autoantibody Standardization Program: interlaboratory comparison of insulin autoantibody assay performance in 2018 and 2020 workshops" (2023)

Summary: This study compared how different labs performed in testing for insulin autoantibodies (IAA) during the 2018 and 2020 workshops. The ADAP assay stood out, showing significant improvements in accuracy over time. In 2020, ADAP achieved a median accuracy score (ROC-AUC) of 0.790, compared to the overall median of 0.736 in 2018.

What the authors say about ADAP: "Among non-radioactive IAA immunoassays, the only submitted ADAP assay, the most recently developed IAA assay format, showed the highest or second-highest pAUC95 and AS95."

https://link.springer.com/article/10.1007/s00125-023-05877-9

Islet Autoantibody Standardization Program 2018 Workshop: Interlaboratory Comparison of Glutamic Acid Decarboxylase Autoantibody Assay Performance" (2019)

Summary: This study reviewed how different labs tested for glutamic acid decarboxylase autoantibodies (GADAs) in the 2018 workshop. The ADAP assay ranked among the top-performing methods, demonstrating strong sensitivity and reliability. It achieved one of the highest scores for detecting true positives while minimizing false positives.

What the authors say about ADAP: "Among [new assays], the PCR-based ADAP assay achieved both high sensitivity and perfect specificity, whereas the rest showed variable performance that in some cases was dramatically inferior to that of more mature formats."

https://academic.oup.com/clinchem/article-abstract/65/9/1141/5608493