What is the sensitivity using this cut-point?

Genetics, Obstetrics
Precise quantification of smoking during pregnancy is difficult in retrospective studies. Routinely collected blood specimens from newborns for screening purposes may provide a low cost method to objectively measure maternal smoking close to the time of delivery. Serum cotinine is an important bio-marker of recent smoking. A study was performed comparing cotinine levels in dried blood spots in newborns with those
in umbilical cord blood (the gold standard) among 428 newborns in the California Genetic Screening Program (Yang et al. [11]). The lowest detection limit for dried blood spot cotinine was 3.1 ng/mL. The data in Table 3.9 were presented relating dried blood spot cotinine determinations to umbilical
cord blood cotinine determinations.

Table 3.9: Distribution of Cotinine Level in Dried Blood Spots from Newborns by Maternal Active Smoking Status* close to the time of delivery among 428 babies delivered in California, 2001€“2003

*Maternal active smoking at the time of delivery was defined as cord blood levels of ‰¥10 ng/mL.

Suppose a cutoff of ‰¥ 5 ng/mL is proposed as a criterion for testing positive based on dried blood spot cotinine levels.

Transcribed Image Text:

Matemal Active Blood (ng/mL) Smoking = yes Smoking = no Cotinine Level in Dried Cotinine Level in Dried Blood (ng/mL) Maternal Active Smoking = yes Maternal Active Smoking = no Maternal Active 2 326 2 3 <3.1 10 2 3.1 4. 11 3 2 12 13 6. 76 214 8. 337 Total 91 NO O ON - - 3.