Lh. Bernstein et al., AMNIOTIC-FLUID POLARIZATION OF FLUORESCENCE AND LECITHIN SPHINGOMYELIN RATIO DECISION CRITERIA ASSESSED/, The Yale journal of biology & medicine, 68(3-4), 1995, pp. 101-117
A negative finding of amniotic fluid (AF) phosphatidyl glycerol (PG) d
oes not eliminate the need for determining the lecithin/sphingomyelin
ratio (LSR). We use a novel approach to classify fetal lung maturity (
FLM) data, and to validate the fluorescence polarization (FP) surfacta
nt assay (Abbott), which replaces the PG assay and reduces the frequen
cy of repeat LSR. This method finds the values (decision points) of th
ese tests that allow for classifying the data with least errors. These
tests best identify the risk of respiratory distress syndrome (RDS) f
rom fetal lung immaturity. We find the decision values for tests by ex
ploring the data for information content and optimize their selection
using group-based reference. We previously defined normal reference as
the maximum entropy set with no information. The uncertainty resolved
by information provided in the data allows formation of syndromic cla
sses. This is greatest at the values for the variables (decision-point
s) associated with the greatest decrease in entropy. Decision-values f
ound for PF, EGA, PG, LSR that classify amniotic fluids into the matur
e and not-mature classes are in agreement with the results of ROC anal
ysis. We validate the replacement of PG by the PF method. We also find
a level of FP below which LSR might be required to resolve uncertaint
y and above which the FP indicates maturity. We confirm the ability to
evaluate fetal maturity methods using information analysis.