Arun:
Very interesting question. I have been interested in RCA Folate because of
its implication for NTD. (A study out of Ireland in 1996 had shown a dose
response relationship between RBC Folate and NTD). In the late 1997 both US
and Canada added folic acid to flour. I reviewed some 1000 RBC Folate
results from general practice submitted to a private lab during the year
1995 (you had visited this lab!). I also had the hematology work up on
these women. Starting with a sample size of about 1000, I was able to
select those women in childbearing age and who were "normocytic". Final
sample size was about 225. (Yes, you could legitimately argue this is a
very selected population where the reason for requesting RBC Folate was not
know to us. Most likely the reason for the request was investigation of
anemia as you have suggested.) I repeated the same analysis in samples
collected in the early 1998 after the addition of folic acid to flour. My
analysis of women in child bearing age (14-45) who were normocytic, the
mean RBC Folate has increased from ~580ng to ~830ng from 1995 to 1998!!! We
have just submitted this data to CMAJ a few week ago - hopefully they will
accept and publish it. Our take is NTD - suggesting that although the mean
level has increased there still is a large percentage of women who may be
at risk for NTD so folic acid supplementation should be continued. Another
study from the States published last year (NEJM) has also shown a mean rise
in serum Folate since the addition of folic acid. The difference between
our data and the published data is that ours is a very well defined female
population (albeit some biases) and we show RBC Folate data which is a
better indicator of body stores.
So it is not surprising that you are seeing fewer and fewer low Folates!!
In my view we need to revisit RBC Folate again from different perspective.
regards
bhushan
-------
At 12:20 PM 05/10/00 -0700, Garg, Arun wrote:
>Is determination of serum and RBC folate still useful? Our review of data
>shows very low frequency of abnormal serum and RBC folate in nonpregnant
>adult population. What is the experience of other members of this mail bag.
>Most of our requests for folate are with order for vitamin B12, I presume
>due to teachings of anemia and vitamin B12 and folate interrelations.
>comments or suggestions will be much appreciated either on the mail bag or
>directly. Thanks
>
>Arun Kumar Garg,MD,Director,
>Laboratory Medicine and Pathology
>Royal Columbian Hospital/SFHR
>330 East Columbia Street, New Westminster,BC
>Canada; V3L 3W7
>604-520-4330(voice); (604)-520-4769 (fax)
>[log in to unmask]
______________________________________________________________
Bhushan M. Kapur, D.Phil, C.Chem, FRSC, FACB, FCACB
[log in to unmask]; [log in to unmask]
Consultant in Toxicology
Assistant Professor of Clinical Biochemistry
Department of Laboratory Medicine and Pathobiology
Faculty of Medicine, University of Toronto
&
Division of Clinical Pharmacology and Toxicology
The Hospital for Sick Children
Toronto, ON M5G 1X8
homepage: http://www.clinitox.com
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