Fetal Lung Maturity (FLM)—Lamellar Body Counts (LBC)

Most common test currently use in the United States. LBCs are concentrically layered "packages " пїЅ of phospholipids produced by type II pneumocytes. LBCs represent the storage form of surfactant. They are present in amniotic fluid in increasing quantities as gestation advances. They are similar in size as platelets and can be counted in most hematology analyzers.

Normal range:

Mature fetal lungs: ≥50,000/ пїЅ пїЅL

Borderline: 15,000 " пїЅ50,000/ пїЅ пїЅL

Immature fetal lungs: ≤15,000/ пїЅ пїЅL

Use

Predicting FLM and assessing the risk of developing neonatal respiratory distress syndrome, when performed during 32 " пїЅ39 weeks of gestation

Interpretation

Increased in mature fetal lungs

Decreased in immature fetal lungs

Limitations

It is as accurate as TDM/FLEXII FPIA method (no longer available) surfactant/albumin ratio.

LBCs not indicated >39 weeks of gestation.

Amniotic fluid samples should be free of blood or meconium contamination.