What Is The Difference Between HCG And Free Beta HCG?
I am asking because I want to know if a high hcg (mIU/ml), which is on high end of normal range could correlate with a high free Beta hCG measured in ng/ml when screening is done at the end of first trimester.
They are independent values ma'am
Detailed Answer:
Hello ma'am and welcome.
Thank you for writing to us.
There are different forms of hCG present ma'am, out of which total hCG and free beta hCG are few. Other forms of hCG include C-terminal peptide total hCG, alpha hCG, pituitary hCG, etc.
As for your doubt, a high total hCG does not have to correlate with high free beta-hCG levels. They can be completely independent.
For example, from a recent study high levels of total hCG, free beta-hCG and low levels of AFP (alpha fetoprotein) have found to be related to various trisomy abnormalities in the fetus.
Also found in a recent study was that free beta-hCG was more beneficial in screening for Down syndrome (a chromosomal abnormality) than total hCG.
I hope you find my response both helpful and informative ma'am. Please feel free to write back to me for any further clarifications, I would be more than happy to help you.
Best wishes.
Is the hCG that is tracked in early pregnancy the free beta-hCG? Or is the test based on total hCG?
I was looking at betabase.com and it shows median hCG numbers in early pregnancy, and it's in mIU/ml. It seems that free Beta hCG is measured in ng/ml.
This would imply that they are different measurements. Are they different?
Thank you.
They are different values ma'am
Detailed Answer:
Hello once again ma'am.
In early pregnancy, total hCG is measured ma'am.
You are quite right ma'am, they are different values and total hCG is the marker used to detect pregnancy, whereas, free beta-hCG is more beneficial in detecting chromosomal abnormalities. They most certainly are different values ma'am.
I hope this information helps. Please feel free to write back to me for any further clarifications, it would be my pleasure to assist you.
Best wishes.