The ubiquitous presentation of this theory has, inevitably, closed minds to the possibility of alternative theories by which the addition of AA could produce an increased MA (or RFBP) response.
Both MA and RFBP assay response to deconjugated RCF (5C[H.sub.3]-[H.sub.4]-PteGlu) is pH dependent (12,15).
Therefore, the assumption that the availability of hemolysate folate for terminal MA or RFBP assay is not affected by folate binding to any erythrocyte or plasma component is false.
One report in the literature (30) (the implications of which appear to have been overlooked) reported that the degree of Hb oxygenation altered RCF amounts such that deoxygenation increased, and oxygenation decreased, assayable folate concentration in both MA and RFBP assays.