Sputum eosinophilia more common than increase in FeNO after occupational challenge

Induced sputum and FeNO measured before, at 7 and 24 hours after specific challenge.A 2.2% increase in sputum eosinophils post challenge had a sensitivity 74-79 % (at 7 and 24 hours) and a specificity of 81% aginst specific challenge in 20 challenge positive and 16 challenge negative subjects (post hoc analysis). FeNO showed no significant change at 7 hours, an increase >10ppb at 24 hours had a sensitivity of 37% for a specificity of 81%. The next stage would be to test the 2.2% increase in eosinophils is subjects whose challenges were equivical in terms of FEV1 decline, or who showed a <20% FEV1 fall post challenge. The mean FEV1 fall in this group was high at 30% (SD 11.45). 14/26 had immediate reactions aline.

References

	Lemiere C, D'Alpaos V, Chaboillez S, Cesar M, Wattiez M, Chiry S, Vandenplas O , Investigation of occupational asthma: sputum cell counts or exhaled nitric oxide?. , Chest , 2010 ; 137 : 617-622

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