Blood collected with an
anticoagulant is beneficial for simultaneous evaluation of immune cells and humoral components such as
antibodies. However, it is critical that the
anticoagulant does not affect quantitative and qualitative analyses of
antibodies. In the present study, we examined the potential interference of the widely used
anticoagulants heparin,
EDTA, and
acid citrate dextrose (ACD) on vibriocidal antibody activities and Vibrio cholerae
lipopolysaccharide (LPS)-specific
IgG,
IgM, and
IgA levels in the plasma and sera obtained from
cholera patients or vaccinees. Serum vibriocidal antibody titer was inhibited in the presence of
EDTA or ACD but not in the presence of
heparin. Moreover, 100% (8/8) of the vibriocidal antibody titers of plasma samples obtained from the vaccinees in tubes containing
heparin were identical to the titers of matched sera when compared with 37.5% (3/8) and 50% (4/8) of the plasma samples prepared with
EDTA and ACD, respectively. Among LPS-specific Igs, the Pearson correlation coefficient (r) for
IgA in serum and plasma was low (r = 0.716), and the coefficients for
IgG and
IgM were relatively high (r = 0.997 and r = 0.945, respectively) in heparinized plasma samples compared with the coefficient for
IgG and
IgM of
EDTA- and ACD-treated plasma. Our results suggest that
heparin is an appropriate
anticoagulant for the collection of blood when measuring vibriocidal activities and antibody levels in plasma samples.