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Published on: August 17, 2022
The Clinician-reported Genetic Testing Utility Index (C-GUIDE) for Prenatal Care: Initial evidence of content and
Robin Z Hayeems1, Stephanie Luca2, Bowen Xiao2
1Program in Child Health Evaluative Sciences, The Hospital for Sick Children, Toronto, ON, Canada; Institute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, ON, Canada.
Purpose:
To develop and assess the face and construct validity of the Clinician-reported Genetic Testing Utility Index (C-GUIDE) for genetic testing in prenatal care.
Methods:
After a literature review and consultation with clinical experts, a preliminary draft of C-GUIDE Prenatal was developed. Its face and content validity were then assessed by 19 prenatal genetics' providers using interviews and surveys. Feedback informed further revisions. To test construct validity, 4 geneticist raters completed C-GUIDE on a retrospective sample of cases that received prenatal genetic testing and completed a concurrent global assessment of utility of these cases using an anchor item. A generalized estimating equations model was used to adjust for rater correlation and measure the association between C-GUIDE scores, global item scores, and potential clinical variables.
Results:
To develop C-GUIDE Prenatal, 7 items were removed, 10 items were modified, and 4 items were added. For 101 cases rated for validation, on average, a 1-point increase in the global item score was associated with an increase of 1.1 in the C-GUIDE score (P = .04). Compared with uninformative results, informative positive and informative negative results were associated with a mean increase of 10.7 (SE = 1.05) (P < .001) and 5.6 (SE = 1.85) (P < .001), respectively. As indications for testing, known/familial variants were associated with a mean increase in the C-GUIDE score of 4.7 (SE = 2.21) (P < .001) compared with ultrasound findings. C-GUIDE scores increased by a mean of 3.0 (SE = 0.23) among cases for whom pregnancies were ongoing compared with those for whom they were not (P < .01).
Conclusion:
The significant positive associations between C-GUIDE total and the global item score and between C-GUIDE total, result type, indication for testing, and pregnancy status in the expected directions provide evidence of construct validity.
