Barbara I think that must be a different test. Look up KI-67 .

A Ki-67 score is a measurement of how quickly cancer cells are dividing. A higher Ki-67 score indicates that the cancer is likely to grow and spread.
What is Ki-67?
Ki-67 is a protein found in cells that are dividing
It's also known as the Ki-67 proliferation index
A pathologist uses a special stain to measure the Ki-67 value
What does a Ki-67 score mean for treatment?
A Ki-67 score can help doctors decide which treatment is best for a patient
For example, the FDA has approved CDK inhibitors for people with tumors that have Ki-67 levels of 20% or higher
What are some Ki-67 score ranges?
A Ki-67 score of 2% or lower is considered grade 1
A Ki-67 score between 3% and 20% is considered grade 2
A Ki-67 score of more than 20% is considered grade 3

It kind of makes it a little better, doesn't it ? Like I said for my stage 4 cancer and only 3 lesions to bone since diagnoses and on anastrozole I would say my 10% Ki-67 is accurate .

The lower the number the slower growing it is. Mine is 10% and considering I am stage 4 my cancer has been very slow growing with very little treatment.

Correction Carol, I just double checked. They gave the result of Ki-67 with the tissue during biopsy.

there is a blood test for KI but the KI-67 is in relation to how quickly cancer cells are dividing. Everyone who has had a Breast biopsy has a KI-67 result.