Diagnostic Accuracy of Transbronchial Biopsy in Acute Farmer’s Lung Disease: Results Diagnostic Distribution

15 Mar
2014

Diagnostic Accuracy of Transbronchial Biopsy in Acute Farmer’s Lung Disease: Results Diagnostic DistributionResults Diagnostic Distribution
A blinded analysis of 105 TBB specimens was performed, the pathologists knowing that there were cases of FL but not the absolute number. Fifty-five of the TBB specimens were from patients with FL. Distribution of diseases from the remaining 50 specimens forming the control group was as follows: sarcoidosis, 21 cases; infectious processes (other than tuberculosis and Pneumocystis carinii), 5; idiopathic pulmonary fibrosis, 3; silicosis, 2; tuberculosis, 2; idiopathic bronchiolitis obliterans, 2. Single cases of following conditions were also included: lymphoma-toid granulomatosis, radiation pneumonitis, pulmonary vasculitis, and necrotizing sarcoid granulomatosis. Eleven patients had TBBs on parenchymal infiltrates for which no definite diagnosis other than nonspecific fibrosis has ever been made. However, FL (or any other type of hypersensitivity pneumonitis) was not considered in the differential diagnosis of these patients, and at BAL, no lymphocytic alveolitis was found. cialis professional

Interobserver Agreement
Pathologic Criteria: For “diffuse lymphocytic infiltration” and “granuloma,” Pearson’s coefficients of correlation were, respectively, r=0.40 (p = 0.002) and r=0.69 (p<0.0001). “Focal lymphocytic infiltration” was discarded as a diagnostic criterion since no relationship was found between scores attributed to focal infiltrations by both pathologists (r=0.06; p=0.69), suggesting that each was considering different pathologic patterns when referring to this criterion.
Overall Assessment: The level of agreement between the pathologists was fair (weighted kap-pa=0.29; 95% Cl, 0.17 to 0.42) (Table 1). Eleven of the 105 specimens (10.5%) were called “probable FL” by the first observer, as opposed to 39 of 105 biopsy specimens (37.1%) by the second observer (p = 0.10). Also, there was no significant difference between the pathologists in the proportion of cases called “possible FL” (27/105 [25.7%] vs 23/105 [21.9%]; p=0.59). However, there was a significant difference in the proportion of cases called probable FL or possible FL (38/105 [36.2%] vs 62/105 [59.0%]; p = 0.0004). This result suggests that the differences were not simply related to the varying diagnostic thresholds between the words probable and possible, but to true differences in diagnoses.

Table 1—Interobserver Agreement Study on the Overall Assessment of the Biopsy Specimens

Observer 1
iProbableFL PossibleFLNonspecific iAlternateDiagnosis
Observer 2 Probable FL71411rf
Possible FL37130
Nonspecific15220
Alternate diagnosis0159
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