J. Dassarma et al., DIRECT MICROTITRE PLATE ENZYME-IMMUNOASSAY OF FOLIC-ACID WITHOUT HEATDENATURATION OF SERUM, Journal of immunological methods, 184(1), 1995, pp. 7-14
A new and simple method for enzyme immunoassay of folic acid (FA) has
been developed, which does not require extraction or heat denaturation
of serum. FA-free serum for standards was prepared by a new immunosor
bent technique as conventional methods were unsuccessful. The detectio
n limit of the assay is 0.05 ng/ml. Intra- and interassay variabilitie
s ranged between 5-13.3%. Analytical recoveries obtained after spiking
with different amounts of FA ranged between 93-110%. We eliminated th
e interference of endogenous folate binding protein - a major problem
in direct FA assay by incubating serum samples (or standards) with FA-
HRP conjugate in antibody coated plates at 50 degrees C. Comparison of
our data with results obtained by microbiological assay and also by h
eating samples in alkaline buffer showed good correlation.