I used to use the Roche method. It was my understanding that it cross-reacted with the LH beta-core degradation fragment that accumulates when post-menopausal women have a chronically high LH. Our studies showed the apparent hCG in post-menopausal samples ranging up to 9 mIU/mL, so we set a different cutoff and interpretive comment depending on age.
 
Gary Sandberg MT(ASCP) SC
chemistry supervisor
St.Joseph Hospital
Bellingham, WA  USA
 
 -----Original Message-----
From: Clinical biochemistry discussion list [mailto:[log in to unmask]]On Behalf Of Grimes, Helen, UCHG
Sent: Monday, August 08, 2005 7:45 AM
To: [log in to unmask]
Subject: Cut off levels of hCG (intact +b) for pregancy using Roche Elecys E 170

Roche found that serum for non pregnant premenopausal women - 97.5% =<1 mIU/mL, but the upper 95% confidence limit of the 97.5% percentile ranges up to 5.3 mIU/mL. Then they also found that for 181 non pregnant premenopausal women, 98.9% had values =<2 and the balance of 1.1% were =<7 mIU/mL . So what are various laboratories using this method taking as their cut-off?

If one took =<7 mIU/mL, one should not have any false positives, but one could miss very early pregnancy, however, do we know that damage could occur to a developing embryo at such low hCG levels? If most Radiology departments are relying on urinary pregnancy tests, then this level would not be detected anyway?

___________________________________________________________
This message is intended solely for the use of the individual and entity to whom it is addressed, and may contain information that is privileged, confidential, and exempt from disclosure under applicable state and federal laws. If you are not the addressee, or are not authorized to receive for the intended addressee, you are hereby notified that you may not use, copy, distribute, or disclose to anyone this message or the information contained herein. If you have received this message in error, immediately advise the sender by reply email and destroy this message.

------ACB discussion List Information-------- This is an open discussion list for the academic and clinical community working in clinical biochemistry. Please note, archived messages are public and can be viewed via the internet. Views expressed are those of the individual and they are responsible for all message content.

ACB Web Site http://www.acb.org.uk List Archives http://www.jiscmail.ac.uk/lists/ACB-CLIN-CHEM-GEN.html List Instructions (How to leave etc.) http://www.jiscmail.ac.uk/