Practical application and validation of the 2018 ATS/ERS/JRS/ALAT and Fleischner Society guidelines for the diagnosis of idiopathic pulmonary fibrosis

Table 4 Test characteristics of CT categories for diagnosis of histopathologic UIP or Probable UIP

	UIP	Probable UIP	Indeterminate for UIP	Alternative diagnosis
PPV	0.93 (0.68, 1.00)	0.46 (0.19, 0.75)	0.30 (0.07, 0.65)	0.29 (0.18, 0.41)
NPV	0.69 (0.58, 0.78)	0.60 (0.49, 0.71)	0.58 (0.47, 0.68)	0.39 (0.24, 0.57)
Sensitivity	0.34 (0.20, 0.51)	0.15 (0.06, 0.29)	0.07 (0.02, 0.20)	0.44 (0.28, 0.60)
Specificity	0.98 (0.91, 1.00)	0.88 (0.77, 0.95)	0.88 (0.77, 0.95)	0.25 (0.15, 0.38)

Test characteristics, including positive predictive value, negative predictive value, sensitivity, and specificity were determined for all CT categories as compared to histopathologic classification of UIP or Probable UIP (combined). To quantify the uncertainty of these estimates, 95% confidence intervals were computed

ISSN: 1465-993X