We evaluated these findings using our "in house" microbiological assay (2) and fresh clinical EDTA-WB samples.
2, to dilute both red cell hemolysates and folic acid calibrators before microbiological assay, whereas we used 5 g/L sodium ascorbate (25 mmol/L).
After deconjugation and subsequent lysate dilution before microbiological assay, centrifugation of samples revealed the presence of small red pellets in the freeze-thawed samples that were not seen in saponin-treated samples.
The microbiological assay is more tolerant of the presence of polyglutamate RCF forms and will tend to underestimate total folate where hemolysis is complete but deconjugation is not.
The microbiological assay was carried out on microtiter plates with the chloramphenicol-resistant strain of Lactobacillus casei , and the radioassay was performed with the Dualcount Solid Phase Boil assay (Diagnostic Products Corp.
Table 1 shows that, overall, the microbiological assay gives higher values than the radioassay, as reported in the literature [2, 11].
A variety of disposable vials can be used to perform several microbiological assays
, including total aerobic count (TAC), Yeast and Mould (YM), coliform (CM), E.
Currently, the major analytical approaches used for folate determination are microbiological assays
, radioassays, chemiluminescence assays, HPLC, and ion-capture assays.