Re: AFP triple re-calculations
From: art fougner, md (evsono@pipeline.com)
Wed Jan 31 08:37:18 2001
another caveat with date adjustment is that Down's fetuses have shorter
femurs. if you are readjusting risks based on second tm data, would
suggest simply using bpd.
art
At Wed, 31 Jan 2001, Dr. Lynn Montgomery wrote:
>
>There was an abstract at SMFM last year I believe where is was demonstrated
>that unless there is a 2 week disparity between the dates and U/S biometry,
>recalculation did not significantly change the risk. Although certainly not
>a controlled study, I have found that to be fairly true in my practice.
>Lynn
>
>-----Original Message-----
>From: ob-gyn-l@obgyn.net [mailto:ob-gyn-l@obgyn.net]On Behalf Of
>Griffiths Malcolm (RC9) Luton & Dunstable Hospital TR
>Sent: Wednesday, January 31, 2001 2:43 AM
>To: Multiple recipients of list OB-GYN-L
>Subject: Re: AFP triple re-calculations
>
>The triple test is effectively calibrated to the US biometry or dates. You
>must use the US gestation in calculating the serum screening risk, even if
>you don't think the EDD needs revising.
>
>Jason Gardosi and others though would probably argue that you should always
>revise the EDD to the US dates no matter how small or large the difference
>between LMP and US.
>
>-----Original Message-----
>From: garrys@mindspring.com [mailto:garrys@mindspring.com]
>Sent: 31 January 2001 03:12
>To: Multiple recipients of list OB-GYN-L
>Subject: OB: AFP triple re-calculations
>
>I am aware that AFP triple screening is dependent on dates, and I
>believe that the ultrasound EDC from a first trimester scan is "better"
>than the LMP generated date.
>
>So, now you see a patient at 8 to 9 weeks, and her LMP is
>perfect/regular/known/28 days/no pills/yada, and her vagscan is within 5
>days. If you are like me, her EDC is based on the LMP, and that's
>that--the scan corroborates it, but doesn't change it.
>
>Now, she's 16.3 weeks, and the triscreen is abnormal with an increased
>Down risk of 1:215 (she is 32 years old), using 16 weeks, which was
>based on the LMP.
>
>Do you ask the lab to recalculate, in that if you use the scan EDC, it
>makes her 15.7 weeks when the test was done?
>
>Garry
>
>--
>Garry E. Siegel, M.D., F.A.C.O.G.
>Roswell, GA
>Private Practice
>
--
art fougner, md
A series of 1000 cases begins with but a single anecdote.
