Question

1. A fetus has a ΔOD 450 that is borderline between intermediate and high risk for HDN, and the mother’s Anti-D titers are rising. After running a L/S chromatography test, the area of the lecithin spot is approximately 1.2 cm2 and the area of the sphingomyelin spot is 0.68 cm2. Are the baby’s lungs reliably mature? Can you go ahead with an emergency c-section? If not, what treatment is immediately appropriate?

2.What are two causes of a positive fetal fibronectin test that are not indicative of premature labor?

3.describes three alternate procedures in place of the technically complex L:S ratio. Of those three, which would you recommend for your lab if you were a laboratory director, and why?

Answer 1

1. Baby lungs are not mature as the lecithin: sphingomyelin ration is less thsn the minimum limit of 2:1. So the baby is at risk of breathing problems. We can give Betamethasone to the mother if going to deliver prematurely.

2. False positive test for fetal fibronectin will occur when the test done just after sexual intercourse or after digital cervical exam.

3. Alternate methods are lamellar body count, phosphatidylglycerol, Surfactant- Albumin ratio, Fluorescence polarization.

If i were a Lab director, I would prefer lamellar body count in Amniotic fluid as it is quick, simple, universaly available, cost effective to assess fetal lung maturity.