Phosphatidylglycerol and Phosphatidylinositol Content

 

Specimen: Amniotic fluid, protected from light

 

Testing Methods: Phospholipids can be measured using thin layer chromatography, enzymatically or by agglutination methods.

 

Interpretation:

• phosphatidylglycerol > 2 µmol/L or > 2% of total phospholipid ("positive" or "present"): indicates fetal maturity

• phosphatidylinositol > 15% of total phospholipid ("positive" or "present"): indicates fetal maturity

• the presence of phosphatidylglycerol has a high predictive value of no respiratory distress in the infant

• the absence of phosphatidylglycerol can have a low predictive value for occurrence of respiratory distress (depending on population studied), resulting in a high false immaturity rate

 

Interferences: Not affected by many of the disorders limiting the L/S ratio (maternal diabetes mellitus, erythroblastosis fetalis, contaminants in amniotic fluid)