M. Jenkins et A. Vickers, Unreliability of IgE/IgG4 antibody testing as a diagnostic tool in food intolerance, CLIN EXP AL, 28(12), 1998, pp. 1526-1529
Background Some clinicians link chronic disease in certain patients to 'foo
d intolerance'. This is currently diagnosed by exclusion dieting, a time-co
nsuming and tedious technique. It has been claimed that IgE/IgG4 antibody t
esting is a rapid and valid method of determining food intolerance.
Objective To determine the test/retest reliability of IgE/IgG4 antibody tes
ting as a diagnostic tool.
Methods Blinded testing of duplicate blood samples from nine patients with
suspected food intolerance was undertaken by tertiary referral centre using
the services of a commercial laboratory. The proportions of consistent and
inconsistent results for tests of 95 different foods were analysed.
Results Test/retest reliability was low. Even though the study method syste
matically overestimated kappa, this value never exceeded 0.51, regardless o
f the statistical model used. All but one patient had a greater number of i
nconsistent results than had been prespecified as an unacceptable level of
disagreement. In one case, 50 out of 95 test results were inconsistent on r
etest.
Conclusions We found no evidence that IgE/IgG4 antibody testing as performe
d by this laboratory is a reliable diagnostic tool.