Idiopathic Pulmonary Fibrosis: Likelihood Ratios

Introduction: also known as Fibrosing Alveolitis (in older literature), it is one type of Interstitial Lung Disease.

The likelihood ratios of findings for Idiopathic Pulmonary Fibrosis are listed below. See the left navigation bar to change the display.

Pre-Test Probability (Prevalence): %.	Post-Test Probability (Predictive Value): %.	Switch to display mode.
Note that calculating probabilities from more than one** finding is inherently inaccurate because findings are not independent. (For example, using two positive findings that share a common pathogenesis is likely to overestimate the true probability.)

Good Positive and Negative Likelihood Ratios
Finding	Result	+LR	-LR
[ + ] High-Resolution Chest CT (HRCT)	+ 0 -	7.9	0.2
Community patients referred for further definitive diagnostic evaluation of new-onset, untreated nonspecific ILD. Another study found 88% sensitivity (Chest. 1995 Jul;108(1):109-15. PMID: 7606943). Study: Chest. 1999 Nov;116(5):1168-74. PMID: 10559072
[ + ] Clinical diagnosis	+ 0 -	20.7	0.4
Clinical diagnosis includes: history, HRCT, and bronchoscopy (gold standard is lung biopsy). Community patients referred for further definitive diagnostic evaluation of new-onset, untreated nonspecific ILD. Study: Chest. 1999 Nov;116(5):1168-74. PMID: 10559072