Hello, I was recently tested for chromogranin a because of ongoing flushing and stomach issues.

My test was done at Quest and the results were as shown below:

Result: 99 ng/mL
CHROMOGRANIN A, LC/MS/MS
Reference Range: ADULTS: < 1 ng/mL

I understand that different labs have different thresholds but can someone please explain to me why the Quest cut off range is 3 to 6X higher than what is considered normal according to the Carcinoid Cancer foundation website and many other sources? "There is a normal level of Chromogranin A in the blood, and the range currently is less than 39ng/l.. Abnormal levels can vary form forty to the thousands. The sensitivity of the test for CgA is about 80%, this means that 80% of the time abnormal levels are correctly associated with disease."

Does this mean this lab just is not as “careful” or not as concerned about an elevated Cga? Or is it run differently causing it to be more sensitive?

Thanks so much!