Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1117 page)

   Levels are influenced by dietary intake, meals, and exercise.

PHOSPHATIDYLGLYCEROL (PG)

   Definition

   This minor constituent of pulmonary surfactant begins to increase appreciably in AF several weeks after the rise in lecithin.

   Because PG enhances the spread of phospholipids on the alveoli, its presence indicates an advanced state of fetal lung development and function.

   PG determination is not generally affected by blood, meconium, or other contaminants.

   PG can be performed by TLC, so it can be determined alone or in conjunction with lecithin-to-sphingomyelin testing.

   It may be reported qualitatively as positive or negative, where positive represents an exceedingly low risk of respiratory distress syndrome (RDS), or in a quantitative fashion, in which a value 0.3 is associated with a minimal rate of respiratory distress.

   AmnioStat-FLM is an immunologic qualitative agglutination test for determining the presence of PG in AF. This test is specific, sensitive, and rapid. Results are not affected by moderate blood or meconium contamination. It requires <0.1 mL of specimen, which can be obtained by transabdominal amniocentesis or from a vaginal pool.

   
Normal range:

   Mature fetal lung: positive and weak positive

   Immature fetal lung: negative

   Use

   Assessing fetal lung maturity