A COMPARISON OF THE SHAKE TEST, OPTICAL-DENSITY, L S RATIO (PLANIMETRIC AND STECHIOMETRIC) AND PG FOR THE ASSESSMENT OF FETAL LUNG MATURITY/

Our aim was to determine the diagnostic accuracy and reliability of fo ur tests for the assessment of fetal lung maturity (FLM): shake test, optical density at 650 nm (OD650), lecithin to sphingomyelin ratio (L/ S) by planimetry and stechiometry, and presence of phosphatydylglycero l. Amniotic fluid was obtained from 74 patients at various gestational ages. The shake test and the OD650 were performed according to publis hed methods. L/S was determined by TLC (thin-layer chromatography) and the ratio assessed by planimetry and stechiometrically by measurement of organic phosphorus from the chromatographic spots. PG was assessed similarly by TLC. When correlated with gestational age at amniocentes is, all tests correlated positively: shake test (r = 0.46, p < 0.005); OD650 (r = 0.31, p < 0.005); planimetric L/S (r = 0.77, p < 0.005); s techiometric L/S (r = 0.52, p < 0.005) and PG (r = 0.54, p < 0.005). T he diagnostic accuracy of each test was as follows: the shake test and the OD650 bad a sensitivity of 50%, while the steciometric L/S had a sensitivity of 75%; the planimetric L/S and the presence of PG were 10 0%. All four tests demonstrated a specificity greater than 64%, the hi ghest for the PG presence being (83%) and the shake test (86%). Predic tive negative values for lung maturity were > 93% for all tests, with the highest for the planimetric L/S and presence of PG being (100%). T he study confirms that the determination of L/S ratio is still superio r to other tests in terms of overall diagnostic accuracy. In addition, it was found that presence of PG was highly associated with the absen ce of respiratory complications in the newborn.