50: Detection rate for trisomy 21, January 2011 to December 2015 Year True positives False negatives Detection rate 2011 88 25 0.78 95 27 0.78 2012 109 26 0.81 2013 89 18 0.83 2014 2015 95 12 0.89 Table 51: Detection rate for trisomy 13 or 18, January 2011 to December 2015 Year True positives negatives Detection rate 2011 43 16 0.73 38 21 0.64 2012 28 17 0.62 2013 27 15 0.64 2014 2015 30 8 0.79 Detection rate for screening for trisomy 21 by age, ethnicity and deprivation Due to the low number of true positives and false negative results for some groups the detection rates for trisomy 21 have been calculated in aggregate across the five years in order to present more stable rates. Numbers for the youngest and oldest age groups are still very low after aggregation so care should be taken with interpretation of these. Across the other age groups the detection rate for trisomy 21 appears to increase with age from 0.59 (59%) for women 20–24 years to 0.95 (95%) for women 40-44 years (see Table 52). 52: Detection rate for trisomy 21 by age, aggregated 2011 2015 – Age True positives False negatives Detection rate# Positive diagnostic Positive diagnostic test/ test/ infant diagnosis infant diagnosis low increased risk risk screen screen Under 20 years 3 5 - 20–24 years 13 9 0.59 25–29 years 33 15 0.69 30–34 years 91 40 0.69 35–39 years 195 32 0.86 40–44 135 7 0.95 45 and over 6 0 - # Rate suppressed if the number of positive diagnoses was <10.
50: Detection rate for trisomy 21, January 2011 to December 2015 Year True positives False negatives Detection rate 2011 88 25 0.78 2012 95 27 0.78 2013 109 26 0.81 2014 89 18 0.83 2015 95 12 0.89 Table 51: Detection rate for trisomy 13 or 18, January 2011 to December 2015 Year True positives negatives Detection rate 2011 43 16 0.73 2012 38 21 0.64 2013 28 17 0.62 2014 27 15 0.64 2015 30 8 0.79 Detection rate for screening for trisomy 21 by age, ethnicity and deprivation Due to the low number of true positives and false negative results for some groups the detection rates for trisomy 21 have been calculated in aggregate across the five years in order to present more stable rates. Numbers for the youngest and oldest age groups are still very low after aggregation so care should be taken with interpretation of these. Across the other age groups the detection rate for trisomy 21 appears to increase with age from 0.59 (59%) for women 20–24 years to 0.95 (95%) for women 40-44 years (see Table 52). 52: Detection rate for trisomy 21 by age, aggregated 2011 – 2015 Age True positives False negatives Detection rate# Positive diagnostic test/ infant diagnosis increased risk screen Positive diagnostic test/ infant diagnosis low risk screen Under 20 years 3 5 - 20–24 years 13 9 0.59 25–29 years 33 15 0.69 30–34 years 91 40 0.69 35–39 years 195 32 0.86 40–44 135 7 0.95 45 and over 6 0 - # Rate suppressed if the number of positive diagnoses was <10.
antenatal-screening-down-syndrome-other-conditions-monitoring-jan2011-dec2015-may17.docx