In a new blog post, Google researchers explain that their AI known as LYNA — short for Lymph Node Assistant — has reached a level of sophistication that it can now tell the difference between cancer and non-cancer on slides with a stunning 99% accuracy.

Google explains that, in a pair of recently-published research papers, the LYNA tool demonstrated incredible accuracy in determining whether breast cancer had spread to a patient’s lymph nodes. Determining this is a major factor in deciding how a cancer patient might proceed, and can change the treatment options and approach that doctors take when handling a particular case.

Google notes that pathologist diagnosis of lymph node metastases (determining whether or not the cancer has spread) can be quite inaccurate, often due to time crunch and fast-moving decisions in the early stages of treatment. Accuracy of an individual slide can be as low as 38 percent, Google notes while referencing past research.