Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1118 page)

   Determining the ability of fetal lungs to produce sufficient quantities of pulmonary surfactant

   Predicting the likelihood of the development of respiratory distress syndrome if the fetus were delivered

   Interpretation

   Increased in mature fetal lungs

   Decreased in immature fetal lungs

   Limitations

   AmnioStat-FLM is not subject to artifacts associated with other lung surfactant tests.

   TLC test can produce false-positive test results with meconium contamination and vaginal fluid contamination.

   The absence of PG or low levels of PG cannot dependably predict the presence of RDS.

   Diabetes, regardless of glucose control, delays PG production.

PHOSPHOLIPIDS

   Definition

   Phospholipids are a class of lipids consisting of a hydrophilic polar head group and a hydrophobic tail. The polar head group contains one or more phosphate groups. The hydrophobic tail is made up of two fatty acyl chains. In an aqueous environment, the hydrophilic heads of the phospholipid molecules tend to face water and the hydrophobic tails bond together, forming a bilayer, which constitutes a major portion and function of cell membranes. Most of the phospholipids in human plasma are phosphatidyl choline (70– 75%) or sphingomyelin (18–20%). The remaining phospholipids include phosphatidyl serine, phosphatidyl ethanolamine (3–6%), and lysophosphatidyl choline (4–9%).

   
Normal range:
150–380 mg/dL.