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Lamellar Body Count
|Test group||Fetal Lung Maturity|
|Method||Quantitative Automated Cell Count|
|Container type||Sterile collection tube|
|Amount to Collect||1 mL Amniotic fluid|
|Sample type||Amniotic fluid|
|Preferred volume||2 mL Amniotic fluid|
|Min. Volume||0.25 mL Amniotic fluid|
|Processing notes||Do not centrifuge. Transport refrigerated to CB. Send refrigerated to ARUP using test code 0080940.|
|Ref Lab Rejection Criteria||Frozen specimens. Vaginal pools containing mucus. Specimens that contain meconium. Grossly hemolyzed specimens.|
|Normal range||> 50 K/µL|
|Synonyms||Fetal Lung maturity;|
|Turn around times||2-3 days|
|Additional information||Lamellar body count (LBC) testing employs enumeration of lamellar bodies in amniotic fluid as an index of fetal lung maturity and replaces the surfactant/albumin ratio (S/A ratio), which is no longer commercially available. Numerous studies have demonstrated the clinical performance of the LBC as equal to or better than the S/A ratio.
LBC results are reported as >50 x10e9/L (mature), 15-50 x10e9/L (transitional), and <15 x10e9/L (immature). With mature results, there is a very low risk of respiratory distress syndrome (RDS) of the newborn with delivery. With transitional results, the fetal lungs are probably mature, but the possibility of RDS cannot be excluded. With immature results, the fetal lungs may not be mature and the risk of RDS is significant.
Phosphatidylglycerol (PG) testing may be also ordered but will only be performed in cases of transitional LBC results. Note that PG is usually not detectable in significant amounts before 35 weeks gestation. The presence of PG is indicative of fetal lung maturity, however, absence of PG does not necessarily predict development of RDS. Most amniotic fluid samples with LBCs in the transitional range will be negative for PG.
As blood, meconium, and mucous contamination adversely affect the LBC assay, such samples will automatically be submitted to the UCSF Chemistry division for phosphatidylglycerol (PG) testing.
|LDT or Mod FDA?||Yes|
|Last Updated||3/11/2015 9:59:09 AM|