Does this test have other names?L/S ratio Show
What is this test?This test measures the amount of 2 substances that are found in the amniotic fluid during pregnancy. The 2 substances are called lecithin and sphingomyelin. They are surfactants. These are chemicals made by the lungs that help them work correctly. Without surfactants, the small air sacs in your lungs (alveoli) would collapse. This would prevent oxygen from entering the bloodstream. In the last 3 months of pregnancy, your baby's lung surfactants can freely pass into the amniotic fluid. Once the surfactant is in the amniotic fluid, your healthcare provider can measure it. In a normal pregnancy, the amount of lecithin in the amniotic fluid continues to rise. But the amount of sphingomyelin stays about the same. Your healthcare provider will compare the amount of each surfactant. This way, your provider can find out how mature your baby's lungs are. The more lecithin there is compared with the amount of sphingomyelin, the more likely your baby’s lungs are mature. Why do I need this test?You might need this test if you're pregnant and expected to deliver before 39 weeks. Or you may need this test if your healthcare provider doesn't know exactly how many weeks pregnant you are. You likely won't have this test if your baby may be born at less than 32 weeks. At that point, your baby's lungs will be immature. You won’t need a test to show this. In a baby growing in the uterus, the lungs are the most important factor in finding out if a baby is ready for life outside the uterus. Many healthcare providers use lab tests to predict how mature the baby's lungs are before birth. You may be at risk for early delivery if you have any of these conditions:
What other tests might I have along with this test?You may have this test as part of amniocentesis. In this procedure, your healthcare provider collects amniotic fluid to measure several other substances. What do my test results mean?Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you. Test results are given as a ratio of lecithin to sphingomyelin. The range of results are:
In some cases, your healthcare provider may want to see a different result. If you have diabetes or kidney disease, for instance, your provider may want the value to be greater than 3.5:1. This is to make sure that your baby's lungs are mature. How is this test done?This test is done with a sample of amniotic fluid. Amniotic fluid can be collected in 2 ways:
Does this test pose any risks?If amniocentesis is done, the risks can include:
What might affect my test results?Many factors can affect your test results. These include:
How do I get ready for this test?You don't need to get ready for this test. If your water breaks early, it's important to tell your healthcare provider about the amount and color of the fluid. Tell them if it's clear, cloudy, or tinted brown, pink, or red. Which of the following tests would be useful in determining lung maturity?Amniocentesis is most commonly indicated for prenatal diagnosis and for fetal lung maturity.
What assessments detect fetal well being?The tests used to monitor fetal health include fetal movement counts, the nonstress test, biophysical profile, modified biophysical profile, contraction stress test, and Doppler ultrasound exam of the umbilical artery.
Which of the following is the best indicative of lung maturity of a fetus?Because PG appears later in gestation, it is a good indicator of maturity (positive predictive value >95%). Generally, fetal lung maturity testing is not necessary when the gestational age is >39 weeks because fetal lungs are usually mature.
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Fetal Lung Maturity Profile.. Which test does the nurse recommend for the patient to help assess fetal genetic abnormalities?Amniocentesis is most commonly used to: Look for genetic disorders such as Down syndrome or cystic fibrosis – This might be done if another test (like an ultrasound of the fetus or blood tests on one or both parents) suggests that there might be a genetic problem.
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