Quantified scoring of the amniotic fluid surfactant foam test and assessment of factors contributing to false negative test results

Surfactant foam test scores were quantified by measuring the percent ring (%R) of foam produced at the meniscus of the 1:1 dilution tube. A comparison of %R scoring with conventional negative-positive rating of the foam test indicated that the %R value provided a more accurate estimate of the lecithin/sphingomyelin ratio. Based on clinical assessment of the newborn infant, the %R score also reduced the incidence of false negative test results …