This article was published in No 1 of The Rondel (Oct 11, 1999)
The Research & Development Institute of Swedish Health Care (SPRI) suggested in a
recent report (1) that the laboratory testing of plasma homocysteine should replace much
of the erythrocyte folate tests. It is speculated by The Rondel that the decision of SPRI
reflected actual debate in Sweden (2-6)). Homocysteine is a sensitive marker for overt and
functional deficiency of vitamin B12 and folate. New knowledge has shown that functional
folate deficiency may occur below 15 nmol/L of folate in serum of patients due to
hereditary polymorphisms in the gene of methylene tetrahydrofolate reductase (MTHFR)
resulting in reduced enzyme activity. A homocysteine value below the upper reference range
is thought to exclude such functional deficiency as well as functional deficiency of B12.
In contrast, an elevated plasma level of homocysteine does not provide positive proof of
such deficiency states. Apart from nutrient deficiency, elevated levels of homocysteine
may be due to sloppy logistics, impaired kidney function or inborn errors of metabolism.
References
All in Swedish. See Abstract in Swedish
Updated juli 25, 2000