ABSTRACT
Assessment of fetal lung maturity is of great importance in obstetric practice to plan for the future care and proper time for termination of pregnancy. At present, there are many methods used for screening for fetal lung maturity. A good screening test should be simple, easy to perform, rapid, inexpensive and be sensitive and specific. This study was a comparative study of fetal lung maturity assessment by using multiple testing: shake test, tap test and OD 650. These three tests were performed simultaneously and interpreted within 10-15 minutes. The results were compared with lecithin and sphingomyelin ratio (L/S ratio) which was used as the gold standard. L/S ratio > 2 was interpreted as “mature” in this study. Aminotic fluid samples wee obtained from women with uncomplicated pregnancies who underwent amniocentesis for fetal lung maturity testing with consent. All samples were uncontaminated by blood or meconium. The results, analysed from 185 samples studied, showed that the shake test, tap test and OD 650 gave a sensitivity of 79.3%, 87.1%, 76.6% and a specificity of 60.0%, 45.0% and 54.2% respectively, which were not statistically different (P>0.05, Cochran’s test). Screening for maturity using two or more tests gave a sensitivity of 82.7% and a specificity of 55.8% which were also not statistically different when compared with each test. In conclusion, shake test, tap test or OD 650 can be easily used as a simple and sensitive screening method for fetal lung maturity. Multiple testing, performing all three tests simultaneously, did not increase the sensitivity or specificity of the test and is not recommended. The choice of test at a screening method is therefore up to individual preference of depends on facilities available.