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Re: Calculation of Risk for Down From: art fougner, md (evsono@pipeline.com) Fri Feb 23 14:20:33 2001 Messages sorted by: [ date ][ thread ][ subject ][ author ] Next message: art fougner, md: "Re: Ultrasound--diagnosis or treatment?" Previous message: Ph Coquel: "Re: Calculation of Risk for Down" In reply to: Allen Worrall: "Calculation of Risk for Down" Next in thread: Novakov: "Re: Calculation of Risk for Down" philippe jeanty uses the following in the low risk patient - one major anomaly, eg cardiac malformation, HIGH RISK. two soft markers - HIGH RISK. there is an article in the October 2000 White Journal addressing this topic - Verdin, Whitlow, Lazanakis, et al. Ultrasonic markers for chromosomal abnormalities in women with negative nuchal translucency and second trimester serum biochemistry, pp 402-406. art At Fri, 23 Feb 2001, Allen Worrall wrote: > >I am aware that a negative ultrasound can reduce the risk assigned by a >triple screen, by about 50%. > >What about a patient who has a very low risk Down Triple screen result, >but one soft marker is found? Can the soft marker likelihood ratio be >applied to alter the triple screen risk? > >Case in point: 35 year old with 4 previous C Sections, triple screen >risk 1:7600. I found hyperechoic bowel (it seemed to me it was as >echogenic as bone, but I find this a little subjective), 19weeks >gestation, nuchal fold 5.4 mm, and a scan was not requested at 11-14 >weeks. On today's scan I found no other anomalies or "soft" markers. (I >think Dr. Nyberg would consider a nuchal fold of 5 mm or greater as >significant, Dr. Benacerraf 6 mm or greater). > >If we say the nuchal fold was normal (not yet 6 mm or greater): >hyperechoic bowel has a likelihood ratio of 5.5. If we consider her age >related a priori risk, it is ~ 1:302 at twenty weeks. Apply the >likelihood ratio for the hyperechoic bowel and her risk is now ~ 1:56, >clearly an indication for amniocentesis. Also if we use Dr. >Benacerraf's scoring system, age 35 and score 1, amniocentesis should be >recommended. > >Or should the 5.5 likelihood ratio be applied to her triple screen risk >of 1:7600, which would increase her risk to 1:1382,and thus >amniocentesis not indicated? > >I suspect the answer is that the patient should be offered >amniocentesis, but I would like to see what others think about this. > >-- >Joseph A Worrall MD RDMS >Fairbanks, Alaska > -- art fougner, md A series of 1000 cases begins with but a single anecdote. Next message: art fougner, md: "Re: Ultrasound--diagnosis or treatment?" Previous message: Ph Coquel: "Re: Calculation of Risk for Down" In reply to: Allen Worrall: "Calculation of Risk for Down" Next in thread: Novakov: "Re: Calculation of Risk for Down"

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