Risk factors for quantity not sufficient sweat collection in infants 3 months or younger.

Objectives: The purpose is to identify demographic characteristics associated with a quantity not sufficient (QNS) sweat collection in infants 3 months or younger. Methods: History of premature birth, infant race and sex, gestational age at delivery, and weight of the infant were compared with QNS collection. Results: Of 221 sweat collections from 197 infants, 25 were QNS. Infant weight less than 3 kg and history of prematurity were associated with QNS collection (P < .001). Thirteen (30.2%) of 43 infants weighing less than 3 kg had QNS collections compared with 12 (7.9%) of 151 infants 3 kg or more. Twelve (46.2%) premature infants had QNS collections compared with 13 (7.6%) term infants. Lower birth gestational age and corrected gestational age were associated with QNS collections. Six (86%) of seven infants who weighed less than 3 kg, had a history of prematurity, and were more than 54 days old at testing had a QNS result. Sex and race did not correlate with QNS collections. Conclusions: Weight less than 3 kg and history of prematurity are associated with an increased chance of QNS sweat collections.