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Updated: Oct 19, 2026
Biochemical Measurement of Neonatal Hypoxia
Published on: August 24, 2011
The biophysical/biochemical test. A new marker of fetal lung maturity in borderline cases
J J Piazze1, M M Anceschi, L Maranghi
1Second Institute of Obstetrics and Gynecology, La Sapienza University, Rome, Italy.
Objective:
To assess the diagnostic accuracy of the combination of a biophysical (lamellar body count [LB]) with a biochemical test lecithin/sphingomyelin ratio (L/S) for the evaluation of fetal lung maturity (FLM) in cases of intermediate-borderline pulmonary maturity.
Study Design:
We studied 105 cases with one or both intermediate (2.1-2.4:1 for L/S and/or 15,000-19,000/microL for LB) or borderline (2.5:1 for L/S and/or 20,000/microL for LB count) FLM indices and no phosphatidylglycerol who delivered within 72 hours of amniocentesis, excluding multiple gestation and contaminated amniotic fluid samples. The biophysical x biochemical marker (B x B) was calculated by multiplying L/S by the corresponding LB, then dividing by 10(3). By using the ROC curve, a cutoff of 50 was found.
Results:
B x B values were lower in respiratory distress syndrome (RDS) than in the non-RDS group (30 [23-41] vs. 52 [50-70], P < .001; median, 25-75%). All RDS cases had a B x B value < 50. Diagnostic accuracy for B x B was: sensitivity, 100%; specificity, 83%; positive predictive value, 61%; negative predictive value, 100%. Sensitivity and positive predictive values were higher for B x B than L/S.
Conclusion:
B x B may be a useful tool for cases with borderline FLM.
