Glenn E Palomaki1, C Sue Richards. 1. Department of Pathology and Laboratory Medicine, Women & Infants Hospital and the Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA. gpalomaki@ipmms.org
Abstract
PURPOSE: Documenting high analytic validity of the molecular diagnostic test for Huntington disease is important because of counseling implications. This dominantly inherited adult onset disorder (prevalence of three or more per 100,000) is characterized by chorea, ataxia, and personality changes. The molecular basis is excessive CAG repeats in the HTT gene. METHODS: External proficiency testing survey results for Huntington disease were extracted (2003-2010). Analytic interpretations and CAG repeat lengths were compared with published performance criteria. RESULTS: Between 2008 and 2010, 33 US participating laboratories reported clinical test interpretations. Analytic validity was high (sensitivity: 99.5%, 95% confidence interval: 97.1-99.9%; specificity: 99.2%, 95% confidence interval: 97.1-99.9%). Repeat length errors occurred in 2.6% (95% confidence interval: 1.8-3.8%) of 1,060 allelic challenges, with most being minor or from a single participant. Past performance (2003-2007) was similar. The 23 international participants had more total repeat length errors (17.5%, 95% confidence interval: 14.6-20.7%). Further analyses indicated that assessment criteria can be relaxed without jeopardizing analytic validity. CONCLUSION: Analytic validity is high for Huntington disease testing among US laboratories. International survey participants had lower analytic validity and a higher proportion of poorly performing laboratories. The reasons for this are unclear.
PURPOSE: Documenting high analytic validity of the molecular diagnostic test for Huntington disease is important because of counseling implications. This dominantly inherited adult onset disorder (prevalence of three or more per 100,000) is characterized by chorea, ataxia, and personality changes. The molecular basis is excessive CAG repeats in the HTT gene. METHODS: External proficiency testing survey results for Huntington disease were extracted (2003-2010). Analytic interpretations and CAG repeat lengths were compared with published performance criteria. RESULTS: Between 2008 and 2010, 33 US participating laboratories reported clinical test interpretations. Analytic validity was high (sensitivity: 99.5%, 95% confidence interval: 97.1-99.9%; specificity: 99.2%, 95% confidence interval: 97.1-99.9%). Repeat length errors occurred in 2.6% (95% confidence interval: 1.8-3.8%) of 1,060 allelic challenges, with most being minor or from a single participant. Past performance (2003-2007) was similar. The 23 international participants had more total repeat length errors (17.5%, 95% confidence interval: 14.6-20.7%). Further analyses indicated that assessment criteria can be relaxed without jeopardizing analytic validity. CONCLUSION: Analytic validity is high for Huntington disease testing among US laboratories. International survey participants had lower analytic validity and a higher proportion of poorly performing laboratories. The reasons for this are unclear.
Authors: Lisa V Kalman; Ira M Lubin; Shannon Barker; Desiree du Sart; Rob Elles; Wayne W Grody; Mario Pazzagli; Sue Richards; Iris Schrijver; Barbara Zehnbauer Journal: Arch Pathol Lab Med Date: 2013-07 Impact factor: 5.534
Authors: Monique Losekoot; Martine J van Belzen; Sara Seneca; Peter Bauer; Susan A R Stenhouse; David E Barton Journal: Eur J Hum Genet Date: 2012-09-19 Impact factor: 4.246
Authors: Devin Oglesbee; Tina M Cowan; Marzia Pasquali; Timothy C Wood; Karen E Weck; Thomas Long; Glenn E Palomaki Journal: Genet Med Date: 2017-06-29 Impact factor: 8.822
Authors: Ida Höijer; Yu-Chih Tsai; Tyson A Clark; Paul Kotturi; Niklas Dahl; Eva-Lena Stattin; Marie-Louise Bondeson; Lars Feuk; Ulf Gyllensten; Adam Ameur Journal: Hum Mutat Date: 2018-07-12 Impact factor: 4.878