Introduction. Respiratory distress syndrome of the newborn caused by the
fetal lung immaturity is a very serious clinical problem. Different tests of
prenatal analysis of amniotic fluid, such as lamellar body count and
Clements? test, are available for predicting the fetal lung maturity.
Material and methods. A prospective clinical study was conducted on amniotic
fluid samples from 2005 to 2006. The amniotic fluid samples were obtained at
the gestational age of 30 to 42 weeks and collected by vaginal amniotomy,
amniotomy during Caesarean section and 72 hours before the delivery by
amniocentesis. A haematology analyzer (Nikon-Kohden?) was used to determine
the lamellar body counts. Clements? test involved adding an equal volume of
96% ethanol to the multiple amniotic fluid volume (1:2, 1:4, 1:16, 1:32),
followed by shaking and noting the presence of ring of bubbles. After the
delivery, we compared the lamellar body count results and Clements? test and
the outcome of pregnancies, primarily the development of respiratory distress
syndrome. The most specific lamellar body cutoffs for maturity and immaturity
were determined according to receiver operating characteristic curves.
Results and Discussion. Out of 232 amniotic fluid samples which were tested,
112 samples were collected after vaginal amniotomy, 88 during the Caesarean
delivery and 32 samples by amniocentesis. The overall incidence of
respiratory distress syndrome was 14.6%. Receiver operating characteristic
curves were used to identify cutoff points for the test. We found that both
tests are good screening tests for predicting the fetal lung maturity with
the area under the curve of 0.782 in Clements? test and 0.751 in the lamellar
body count. Clements? cutoff 2 with sensitivity of 67.6% and specificity of
72.2%, proved best in the prediction of the fetal lung maturity. The lamellar
body count cutoff of 42x10?/?l had the sensitivity of 82.4% and specificity
of 64.6% in predicting the fetal lung maturity. Conclusion. Although both
tests are good in predicting the fetal lung maturity, the lamellar body count
has more advantages, because it is not only more objective, but also
inexpensive, easy and fast to do, requires a small sample volume and is
universally available.
Lamellar body count as a diagnostic test in predicting neonatal respiratory distress syndrome