Always ask your doctors offce to send a copy of your tests. There is more info there than 1 number. You save them and you can compare when you do it again.
It is especially true also when you e.g.do an gallbladder ultrasound. When you read the report you will see besides the gallbladder they mention the spleen, pancreas, size of ducts.
I just called my doctor's office about my gallbladder US, she said the stone was still there but things were fine. What she did not tell me that the size was 4 mm smaller, I asked the nurse that when she did the test. I also want to know the size of the ducts and the gallbladder wall so I can compare to my old tests.
You just can't just go by doctors' views you have to make your own decisions.
If we all listened to our doctors we would have been all without gallbladders.