Prediction of respiratory distress syndrome using the Abbott FLM-II amniotic fluid assay.
BACKGROUND
Most laboratories using the Abbott FLM-II assay for assessing fetal lung maturity follow the manufacturer's recommendations for interpreting the surfactant to albumin ratio (S/A). Thus, values >55 mg/g are considered mature and values <40 mg/g, immature-leaving a wide range of indeterminate values. Little data is available to assist the clinician in interpreting values between 40 and 55 mg/g. The goal of this study was to determine decision levels that would more clearly identify risk for RDS based on S/A results.


METHODS
Respiratory distress syndrome was identified based on medical record review in 46 infants (born at six hospitals), who had S/A measurements on amniotic fluid within 72 h of delivery. An additional 257 women, who had had the S/A test requested but had non-RDS infants, were also identified for this study. The probability of RDS was calculated based on S/A values and on gestational age. Odds ratios were computed for different S/A ratios and different gestational ages.


RESULTS
Probability of RDS increased with decreasing S/A and decreasing gestational age. At gestational age >36 weeks, the probability of developing RDS ranged from 1% at S/A>44 mg/g to 39% at S/A</=20 mg/g. At gestational age <34, the probability of developing RDS ranged from 14% at S/A>44 mg/g to 92% at S/A</=20 mg/g.


CONCLUSIONS
We report a risk-based approach for the clinical interpretation of the results of Abbott FLM-II assays based on a broad range of S/A values and gestational ages.
Kaplan
Lawrence A
LA
Bellevue Hospital, Department of Pathology, New York University, New York, NY, USA.
Chapman
John F
JF
Bock
Jay L
JL
Santa Maria
Edward
E
Clejan
Sanda
S
Huddleston
David J
DJ
Reed
Roberta G
RG
Bernstein
Larry H
LH
Gillen-Goldstein
Jonathan
J
D000418:Albumins / Q000032:analysis*; D000653:Amniotic Fluid / Q000737:chemistry; D005260:Female; D005325:Fetal Organ Maturity; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008168:Lung / Q000196:embryology*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011663:Pulmonary Surfactants / Q000032:analysis*; D012127:Respiratory Distress Syndrome, Newborn / Q000175:diagnosis* / Q000453:epidemiology
D000418:Albumins; D011663:Pulmonary Surfactants