From the Guidelines
The reliability of a fit test, specifically the Functional Intraperitoneal Test, is supported by its sensitivity ranging from 73% to 88% and specificity from 91% to 96% for detecting colorectal cancer, as reported by the USPSTF 1. When considering the reliability of fit tests, it's essential to differentiate between qualitative and quantitative tests. Quantitative FITs, which measure fecal hemoglobin concentration, tend to have more consistent performance characteristics and better quality control compared to qualitative FITs, which have a preset cut-off level for fecal hemoglobin concentration 1. Key points to consider about the reliability of fit tests include:
- Sensitivity and specificity can vary among different FITs and cut points used, with quantitative FITs showing improved detection and positive predictive value for cancer and large adenomas 1.
- Automated and well-studied quantitative FITs have an advantage in consistency of performance characteristics, efficiency, and quality control, allowing for the selection and adjustment of fecal hemoglobin cut-off concentrations to define a positive test 1.
- The ability to adjust fecal hemoglobin cut-off concentrations in quantitative FITs enables the end user to meet endoscopic resource demands and select target clinical sensitivity or positive predictive value for advanced neoplasia detection 1. Therefore, for optimal reliability, quantitative FITs should be used, and the fecal hemoglobin cut-off concentration should be adjusted based on the specific clinical context and endoscopic resource demands 1.
From the Research
Reliability of Fit Test
The reliability of a fit test, also known as a Functional Intraperitoneal Test, can be evaluated based on various studies.
- The study 2 compared three commercially available fit-test methods and found that none of the test methods met the ANSI sensitivity criterion of 0.95 or greater when compared with either of the other two methods.
- Another study 3 assessed the relative impact of fit test exercises and mask donning on respirator fit and found that donning affects respirator fit to a greater degree than fit test exercises.
- A narrative review 4 evaluated the role of fit checking and fit testing of respirators and found that initial fit pass rates vary between 40% and 90% and are especially low in female and in Asian healthcare workers.
- A systematic review 5 compared the effectiveness of fit testing and fit checking for healthcare workers' respiratory protective equipment and found that fit-testing is a method that is more effective, widely adopted, and reliable in assessing the effectiveness of RPE.
- A study 6 involved 225 participants who underwent a fit test using two reusable types of half masks and two types of full masks and found that the passing rate of full masks was higher compared to half masks.
Factors Affecting Fit Test Reliability
Several factors can affect the reliability of a fit test, including:
- Reference method used 2
- Fit test exercises and mask donning 3
- Facial characteristics of the wearer 4
- Type of mask used 6
- Gender and age of the wearer 6
- Educational background and training of the wearer 6
Fit Test Methods
Different fit test methods can be used, including: