Detection of phosphatidylglycerol in frozen amniotic fluid by rapid assay of fetal lung maturity.
OBJECTIVE
The study objective was to analyze the accuracy of the antibody-mediated rapid assay slide agglutination AmnioStat-FLM (Irvine Scientific, Santa Ana, CA) test in detecting the presence or absence of phosphatidylglycerol (PG) in amniotic fluid samples that have been frozen.


METHODS
A prospective blinded evaluation was performed in which fresh samples of amniotic fluid were initially analyzed for PG by the rapid assay (AmnioStat-FLM) test and the results reported for patient management. The specimens were then coded, patient identification was removed and specimens were then frozen. The samples were then thawed and the AmnioStat-FLM test was performed a second time with the laboratory technicians blinded to the original test result. Neonatal outcome and the source of the sample, including the presence of blood and meconium, were recorded.


RESULTS
A total of 200 specimens were evaluated with 197 (98.5%) concordant between the initial test result and the result after the freeze-thaw process regarding the reporting results of either the presence or absence of PG (95% CI 94-99%). The result also was not affected by the source of the specimen or the presence of blood or meconium.


CONCLUSIONS
Freezing and thawing of amniotic fluid had minimal affect on the antibody-mediated rapid assay slide agglutination (AmnioStat-FLM) test result.
Long Beach Memorial Women's Hospital, Long Beach, California, USA. drtowers@rbcpress.com
Craig V
CV
Towers
D000372:Agglutination Tests; D000649:Amniocentesis; D000653:Amniotic Fluid / Q000737:chemistry*; D015331:Cohort Studies; D015925:Cryopreservation; D005260:Female; D005325:Fetal Organ Maturity; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008168:Lung / Q000196:embryology*; D010715:Phosphatidylglycerols / Q000032:analysis*; D011237:Predictive Value of Tests; D011247:Pregnancy; D015203:Reproducibility of Results
D010715:Phosphatidylglycerols