It All Depends What You Count—The Importance of Definitions in Evaluation of CF Screening Performance
Abstract
:1. Introduction
2. Factors to Consider
2.1. Target Disorder
2.2. Screened Population
- If the first step of the algorithm is whether family history or meconium ileus is present, and all are reported as positive screens, then all CF cases within this high-risk group will be counted as detected by screening.
- If the first step of the algorithm is to measure immunoreactive trypsin (IRT), then only those with raised IRT will be reported as screen positive, and those who have a family history but do not have raised IRT (as is common in severe disease, especially with meconium ileus detected [12]) will be counted as missed cases.
- If, following a raised IRT, the second step of the algorithm is CFTR variant analysis using a common CFTR variant panel, the screen will also miss those with family histories and a raised IRT but uncommon CFTR variants that are not included in the panel used.
2.3. Programme Boundaries
2.4. CF Screening Sensitivity Example
- If sensitivity is calculated by counting all missed cases: 89/105 = 84.8%
- If the sensitivity calculation does not include those outside the screened population (i.e., screening declined, family history or meconium ileus) as missed cases: 89/102 = 87.3%
- If the sensitivity calculation only counts missed cases as those which occurred within the laboratory (in-range IRT, no CFTR variants on panel): 89/100 = 89.0%
3. Conclusions
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
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No Other Factors | Other Factors | Screening Boundary | Total | |
---|---|---|---|---|
No screen | 1 declined | 1 | ||
In-range IRT † | 9 | 1 MI †† | 10 | |
CFTR variant not on panel | 2 | 1 FH ††† | 3 | |
Positive screen | 2 normal sweat test | 2 | ||
Total | 16 |
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Heather, N.; Webster, D. It All Depends What You Count—The Importance of Definitions in Evaluation of CF Screening Performance. Int. J. Neonatal Screen. 2020, 6, 47. https://doi.org/10.3390/ijns6020047
Heather N, Webster D. It All Depends What You Count—The Importance of Definitions in Evaluation of CF Screening Performance. International Journal of Neonatal Screening. 2020; 6(2):47. https://doi.org/10.3390/ijns6020047
Chicago/Turabian StyleHeather, Natasha, and Dianne Webster. 2020. "It All Depends What You Count—The Importance of Definitions in Evaluation of CF Screening Performance" International Journal of Neonatal Screening 6, no. 2: 47. https://doi.org/10.3390/ijns6020047
APA StyleHeather, N., & Webster, D. (2020). It All Depends What You Count—The Importance of Definitions in Evaluation of CF Screening Performance. International Journal of Neonatal Screening, 6(2), 47. https://doi.org/10.3390/ijns6020047