CMdeux
Moderator1
Posted: 08.06.2008 at 01:01:20
Excellent!
We have conducted the first study to evaluate the diagnostic value of sesame-specific IgE. We were unable to establish a threshold, in our population, with a 95% positive predictive value. At a sesame-specific IgE threshold of 7 kUA/L, the positive predictive value was 74.1% and did not increase monotonically at higher thresholds.
(So 3 of 4 people with a RAST >7 kU/L are clinically allergic, basically... but the error associated is fairly large.... the only firm statistical conclusion was that if your RAST <0.35 kU/L that you are
really, REALLY unlikely to be allergic.)
Although our study is limited by a small sample of cases, the sample size is similar to that in the study by Sampson5 of wheat and soy IgE, which also did not predict allergy. It is possible that a larger sample would be successful in establishing a threshold. Another potential limitation of our study is that allergy or tolerance to sesame was usually determined by history rather than the gold standard food challenge. Although history is subject to recall and reporting bias, we applied strict inclusion and exclusion criteria. Furthermore, other studies have relied on clinical history to define their allergic cohort.6, 7, 8 The several year delay between convincing reaction and measurement of sesame-specific IgE is also a limitation of our study because it raises the concern that the sesame allergy may have resolved at the time of the IgE measurement.
Good points, all. Particularly the portion I've bolded.
Finally, the portion that I think is most relevant to
this community (as a whole):
Further, the clinician should be aware of the potential for patients with peanut allergy to be falsely labeled as having sesame allergy if this diagnosis is solely based on the sesame-specific IgE. We suggest that if a patient clearly tolerates sesame, it is not warranted to obtain a sesame-specific IgE. Alternatively, if the patient's history is truly convincing of a significant allergic reaction to sesame, regardless of the SPT result or sesame-specific IgE level, the patient should be considered allergic, because anaphylaxis to sesame has been described with negative SPT and IgE levels.
"To travel hopefully is a better thing than to arrive." -Robert Louis Stevenson
USA