Re: over-fasting skews blood-lipid results?

From: Robert (RobertJ_at_hotmail.com)
Date: 03/24/05 

Date: Thu, 24 Mar 2005 00:03:22 -0800

"John Gentile" <yjgent@cox.net> wrote in message
news:BE676024.189C8%yjgent@cox.net...
> in article mOSdndQC4781X9zfRVn-hg@got.net, Robert at RobertJ@hotmail.com
> wrote on 3/23/05 2:23 PM:
>
> >
> > "Jason" <jason@nospam.com> wrote in message news:jason-> Robert,
> >> I was not aware of the newer LDL tests. I'll let my doctor know about
> >> them--she still wants me to fast 12 hours prior to my blood tests. She
> >> told me that if I did not fast for 12 hours that it would have an
effect
> >> on the results.
> >> If you are involved in the medical profession--I'm sure that you know
more
> >> about this subject than I know. I
> >> Jason
> >
> > It is method specific as to whether one has to fast or not. Most places
> > still perform calculated LDL's and those that do must fast and they
usually
> > ask you if you have been fasting or not before they draw the blood.
> > We will switch over to directly measured LDL's after we get our
Architect
> > instrument up and running and will eliminate the data entry or ask
patients
> > whether they are fasting or not.
> > Most doctors are aware of the clinical situations in which a direct LDL
is
> > needed rather than the calculated one.
> >
> >>
> The Triglyceride portion of the Lipid Panel is the test that is most
> sensitive to diet. If you do not fast for the 12 - 14 hours then the
result
> of the triglyceride will be erroneous. The calculation for LDL is done
with
> the Triglyceride, cholesterol and the HDL results. An erroneous Trig will
> give you an erroneous LDL. A direct measure LDL is not based on the Trig,
> but if you don't fast the Trig result will still be wrong.

Not really wrong, only not fasting. The triglyceride is one of the weakest
independant risk factor if you can call it as such. Some people do not
consider it as an indepedent risk factor because of it's inverse correlation
with the HDL. People with high triglyerides tend to have low HDL's. The the
higher the triglyceride then the lower the HDL becomes. There is nothing
intrinsically atherogenic about serum triglycerides. They are crude markers
for atherogenic LDL and other remnant lipoproteins.
When it comes to fasting as in glucose levels, the postprandial collection
is more sensitive in picking up glucose intolerance versus the fasting
glucose. This is especially relevant with
metabolic syndrome and high triglycerides.
The other reason is that a lot of people lie about fasting involving not
only food but alcohol and the formula for a calculated LDL was not intended
for triglycerides higher than 150 mg/dl or very low triglycerides. These
patients have an underestimated calculated LDL.
You avoid all that with an accurate measured LDL in non-fasting persons. You
are really relying too much on the word of somebody who saying that they
fasted and there is no need for that.

>
> --
> John Gentile Editor, Rhode Island Apple Group
> yjgent@cox.net RIAG Web page: www.wbwip.com/riag/
> "I never make mistakes, I only have unexpected learning opportunities!"
>
>
>

Relevant Pages

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