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. Author manuscript; available in PMC: 2016 Feb 4.
Published in final edited form as: Paediatr Perinat Epidemiol. 2013 Oct 10;28(1):3–10. doi: 10.1111/ppe.12083

Table 2.

Cumulative sensitivity and positive predictive value of obstetric estimate of gestational age using early ultrasound as the criterion standard: California Statewide Expanded Alpha Fetoprotein Prenatal Screening Program, April–December 2007 (n = 164 158)

Gestational
age (weeks)		 Sensitivity
[95% CI]		 Positive predictive
value [95% CI]
<28 89.4 [87.1, 91.7] 89.5 [87.3, 91.8]
<32 89.0 [87.5, 90.5] 89.0 [87.5, 90.5]
<34 85.8 [84.5, 87.0] 88.6 [87.5, 89.8]
<36 79.5 [78.5, 80.4] 87.3 [86.4, 88.1]
<37 74.9 [74.1, 75.6] 85.1 [84.4, 85.7]