UTILITY OF A PROVOCATION TEST FOR DIAGNOSIS OF CHRONIC PIGEON-BREEDERS DISEASE

Chronic hypersensitivity pneumonitis (CHP) can be difficult to differe ntiate from other interstitial lung diseases (ILD). To determine the d iagnostic usefulness of a provocation test (PT), 17 patients with CHP induced by avian antigens, 17 with other ILD, and five healthy control subjects were challenged with pigeon serum. After PT, an increase in body temperature (BT) and a decrease in FVC, Pa-O2 and Sa(O2)% were ob served in all patients with CHP and in three with ILD, No reaction was noticed in healthy subjects. ROC curves showed that for FVC the best cut point was a drop of 16% displaying sensitivity (S): 76%, specifici ty (SP): 81%, positive predictive value (PPV): 81%, and negative predi ctive value (NPV): 83%. For a drop of 3 mm Hg in Pa-O2 or 3% Sa(O2), S was 88% for both, SP was 82 and 86%, PPV was 81 and 82%, and NPV was 82 and 86% respectively. An increase of BT > 0.5 degrees C showed S, 1 00%; SP, 82%; PPV, 100%; NPV, 86%. A univariate regression analysis co nfirmed that changes in BT and FVC are predicting values of CHP: RR, 8 2.5 (CI, 10.43 to 651.76) and 1.21 (CI, 1.06 to 1.36). There were no c hallenge test complications. These findings suggest that PT is a usefu l tool for diagnosis of CHP.