Urinalysis and Body Fluids 6th Edition by Majorie DiLorenzo, Susan Strasinger

Exercise 13

A lamellar body count of 50,000 correlates with:

A. Absent phosphatidyl glycerol and L/S ratio of 1.0

B. L/S ratio of 1.5 and absent phosphatidyl glycerol

C. OD at 650 nm of 1.010 and an L/S ratio of 1.1

D. OD at 650 nm of 0.150 and an L/S ratio of 2.0

Step 1 of 2

Lamellar bodies:

Lamellar body is thickly filled layers of phospholipids to facilitate a pulmonary surfactant storage form.

• During the 24 weeks of gestation, lamellar bodies are secreted by fetal lung and are absorbed in the alveolar space to provide surfactant

• They enter amniotic fluid during 26 weeks of gestation and by the end of third trimester, the concentration increases from 50,000 to 200,000 per (micro liter)

• Fetal lung matures during this period along with increased production of lamellar bodies

• Increased lamellar bodies is indicated by increased number of phospholipids and Lecithin-Sphingomyelin (L/S) ratio in the amniotic fluid

• The OD (optical density) is increased with presence of lamellar bodies in fluid

• The concentration of lamellar body is 50,000 , which correlates the OD of 0.150 at wavelength of 650 nm (nanometer) and L/S ratio of 2.0

Therefore, “OD at 650 nm of 0.150 and L/S ratio of 2.0” correlates with the lamellar body count of 50,000. Hence, the correct answer is option.