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Background The morbidity and mortality of hyaline membrane dis- ease (HMD) are quite high due to delayed diagnosis and intervention. Commonly, HMD occurs in preterm infants with surfactant deficiency because of lung immaturity. Lung maturity test could be performed using biochemical, biophysical, and amniotic fluid turbidity test. Objective To find out HMD prevalence and the value of shake test and lamellar body concentration in diagnosing HMD in preterm infants. Methods This was a cross-sectional study carried out at Hasan Sadikin Hospital Bandung on preterm infants born during October- December 2001. The shake test was performed using gastric fluid and amniotic fluid while the lamellar body concentration was per- formed using amniotic fluid. Results During the 3-month period, 571 infants were born, of 64 (11.2%) preterm infants, only 41 (64%) fulfilled the inclusion crite- ria; among those preterm infants, 14 (34%) suffered from respira- tory distress and 7 suffered from HMD (prevalence 17%). All HMD cases occurred in infants less than 32 weeks for gestational age. In 7 preterm infants with HMD, the shake test of gastric fluid ob- tained by lavage showed negative results in 3 and +1 in 4 infants; while the shake test of amniotic fluid revealed negative result in 5 and +1 in 2 infants. Lamellar body concentration of amniotic fluid was ≤18,000/ml in all HMD infants. Among three infants less than 32 weeks for gestational age who did not suffer from HMD, +1 shake test of gastric fluid was found in 2 infants and +2 in 1 infant; while shake test of amniotic fluid showed negative result in 1 infant and +1 in 2; the lamellar body concentration of amniotic fluid was ≤18,000/ml in 2 infants and >18,000/ml in 1 infant. Conclusions We concluded that HMD occurred in 17% of preterm infants. The shake test of gastric and amniotic fluids revealed nega- tive or +1 results whereas lamellar body concentration had value of less than or equal to 18,000/mL. More extensive studies are warranted to assess the validity (sensitivity, specificity and predic- tive values) of these measurements

Summary. The reliability of two rapid bedside tests of fetal lung maturity was investigated in 80 amniotic fluid samples. The results of the ‘tap’ test and those of the shake test were compared with the results of laboratory measurements of phospholipid profiles for fetal lung maturity. The tap test was found to be more reliable with a positive predictive value of 91% and a negative predictive value of 63%, whereas the shake test had a positive predictive value of 79% and a negative predictive value of 31%. The tap test was also more reliable in identifying fetuses with borderline lecithin/sphingomyelin ratios in the range 3.2–3.7:1.

Objective: The aim of the study was to determine the sensitivity, specificity and predictive value of two simple and cheap diagnostic tests of fetal pulmonary maturity (FPM) and compare them with the more complex and expensive phospholipid profile (PP), which includes the determination of phosphatidyl glycerol (PG) and the lecithin/sphingomyelin ( L S ) ratio. Methods: Samples of amniotic fluid were obtained from 70 patients between the 26th and 38th weeks of pregnancy. The PP, shake test and tap test at 2, 5 and 10 min were determined. All patients gave birth within 12 h following these tests and none received corticoids during this period. The neonates were observed for 72 h. The results of the tests were compared with the incidence of neonatal respiratory distress syndrome. Results: The sensitivity of the shake test was 92% for FPM, as was the sensitivity of PP, while for the tap test at 2, 5 and 10 min it was between 96 and 100%. In terms of specificity, the 5- and 10-min tap test diagnoses were 100% correct for immaturity while all other tests were 60–78% correct. The predictive value for maturity was 100% for the tap test (5 and 10 min), 67% for the 2-min tap test, 64% for PG, 60% for L/S and 56% for the shake test. Conclusion: The tap test is a good alternative to other diagnostic methods of FPM. Its use at the bedside, its rapidity and low cost enhance its value.

Neonatal pulmonary maturity was studied by the Clements shake test in gastric aspirate of 52 newborn infants and their results were compared with those of the same shake test performed in amniotic fluid. Visual assessment, acidity, cytology and the shake test showed marked similarities between gastric aspirate and amniotic fluid obtained immediately before delivery. No infants with a positive shake test in amniotic fluid or gastric aspirate developed RDS while 4 of 5 infants with intermediate or negative shake test results developed RDS.

Summary One hundred and six samples of amniotic fluid were analyzed independently by four clinicians for surfactant content, using the shake test and the palmitic acid content of the amniotic fluid. The variation of the results in the 424 shake tests were examined and the shake tests correlated with the palmitic acid levels. A positive shake test to a dilution of 1:4 had a 100 per cent correlation with a mature palmitic acid level over 35 pg./ml., while a positive test at a dilution 1:2 gave a 5.6 per cent false positive rate. A high false negative rate was found, however, and estimates of the chance of a mature surfactant level in relation to the range of shake tests results are given. Eleven patients had low palmitic acid levels in the amniotic fluid prior to delivery and three of the infants developed the respiratory distress syndrome.

Phosphatidylglycerol and the lecithin/sphingomyelin (L/S) ratio were determined, and the shake test was performed, as indicators of fetal lung maturity, in more than 600 patients. A clinical review of the outcome was made in all patients who underwent delivery within 2 days after collection of amniotic fluid. Correlation was made between phosphatidylglycerol, shake test, and L/S ratio results. L/S ratio had a false positive rate of 5%, and a false negative rate of 58.1%. The shake test had a false positive rate of 1.1%, and a false negative rate of 63.5%. Phosphatidylglycerol determination had a false positive rate of 1.8%, and a false negative rate of 26.9%. Phosphatidylglycerol determination is an accurate predictor of fetal lung maturity, and predicts lung immaturity more correctly than do the L/S ratio and shake test.

Summary A new rapid test of fetal lung maturity (the AmnioStat-FLM) was compared with two currently available rapid tests and with 2-dimensional thin-layer chromatography (2-d TLC). Forty-nine specimens of liquor obtained within 72 h of delivery were assessed, 27 of which were contaminated with blood or meconium. The AmnioStat-FLM compared well with spectrophotometry, the shake test and with 2-d TLC. Only the Amniostat-FLM and the 2-d TLC were reliable in the presence of contamination. The results suggest that the AmnioStat-FLM is a reliable, rapid test and unaffected by the presence of contamination.

Results of the "Amniostat-FLM" assay, a rapid semiquantitative test for phosphatidylglycerol, were compared with determinations of the lecithin/sphingomyelin (L/S) ratio, with phosphatidylglycerol measured by two-dimensional thin-layer chromatography, and with results of the "shake test" for 94 specimens of amniotic fluid. Correlation between results with the Amniostat and the other tests was excellent. All four tests are very accurate when predicting lung maturity. The predictive value of a negative test, i.e., that hyaline membrane disease would not occur, was between 92 and 100%. However, the accuracy of predicted lung immaturity is poor. For all four tests, predictions of lung immaturity were incorrect in more than 50% of the cases. Of the 49 infants born within 72 h of testing, none developed hyaline membrane disease when phosphatidylglycerol was detectable by either method or when the shake test indicated fetal lung maturity, but three infants with L/S ratio greater than 2/1 did develop the disease. The Amniostat provides a rapid screening method for detecting phosphatidylglycerol in amniotic fluid, which could well replace the thin-layer chromatographic method for measuring phosphatidylglycerol in the panel of diagnostic tests for fetal lung maturity.

A simplified, single-step shake test has been performed on gastric aspirate samples from 85 preterm infants and a control group of 214 term infants. Respiratory symptoms were seen in 25 of 30 preterm infants with a negative or intermediate test, but in only 2 of 55 infants with a positive test (P less than 0-001). No infant with a positive test developed respiratory distress syndrome (RDS) while RDS developed in 66% of those preterm infants with a negative test. False-negative results were not seen in the preterm group. The gastric aspirate shake test had better sensitivity and selectivity in prediction of clinical outcome than did the amniotic fluid lecithin/sphingomyelin ratio in 37 preterm infants in whom both results were available. Serial shake tests were performed on samples from a number of infants with RDS and the results were seen to change in parallel with clinical recovery. This and other observations suggest that the result of the gastric aspirate shake test depends more upon direct swallowing of fetal lung liquid than on swallowing of amniotic fluid.

Summary One hundred and ninety samples of amniotic fluid were analyzed for their surfactant content by measuring the lecithin-sphingomyelin ratio and performing the simple “shake test”. The value of these tests in predicting the respiratory performance of the baby at delivery is discussed and the limitations of the tests is evaluated. It was concluded that the shake test is valuable only as a screening procedure for deter-mining fetal lung maturity.

NEWBORN intensive-care units have made great strides in treatment of premature infants with respiratory-distress syndrome. Although many such infants can adequately be handled by pediatricians in intermediate-care nurseries, transfer of certain infants with severe respiratory-distress syndrome to special-care nurseries is sometimes delayed, in the hope that they will run the classic self-limited course. Since survival of these infants is partially dependent on early application of appropriate and sophisticated care, it would be helpful to have a simple test to distinguish which babies are deficient in pulmonary surfactant. These babies could then be transferred to the regional intensive-care unit very soon . . .

In a comparison of the lecithin/sphingomyelin (L/S) ratio and the shake test on 212 amniotic fluid specimens, the shake test demonstrated less maturity than the L/S ratio in 34 per cent and more maturity in 6.6 per cent of the samples. Better correlation with the L/S ratio was obtained with the use of a 20 second shake test than a 15 second shake. When delivery of the fetus occurred within 72 hours following amniocentesis, respiratory distress syndrome (RDS) developed in 36 per cent of the patients in whom the L/S ratio was less than 2.0 but in only 12 per cent of the patients when the shake test was transitional or immature.

Amniotic fluid was collected from 105 pregnant mothers without any obstertrical or medical complications between 13–41 weeks of gestation. Simple tests viz. Nile blue sulphate test for cytology and shake test were performed in 92 cases.

178 samples of amniotic fluid have been examined for lecithin/sphingomyelin (L/S) ratio, lecithin concentration, and the "shake" or bubble test. Three cases of respiratory distress syndrome (R.D.S.) occurred with L/S ratios of less than 1·6, and this con- firmed that the L/S ratio is useful for pre- dicting R.D.S. There were no cases of R.D.S. when the shake test was positive in a dilution of 1 in 4 or more, and it appears that this could be a useful screening test for the presence of surfactant in amniotic fluid.

In 1971, Gluck and co-workers’ developed the lecithin-sphingomyelin (L/S) ratio to evaluate pulmonary maturity from a sample of amniotic fluid. It has become the standard test against which other predictors of fetal maturity (“shake test,” microviscometry) must be compared. Determination of the quantity of phosphatidylglycerol. a marker of complete pulmonic maturity, has increased the reliability of the L/S ratio.’ Reports on the effect of meconium on the L/S ratio have been conflicting: Some authors have reported an increase and others have found a decrease in the values obtained. Studies in our laboratory have shown that meconium has a variable pattern on a two-dimensional chromatogram. As a result, the effect on the lecithin and sphingomyelin spots is variable and unpredictable. Since phosphatidylglycerol encompasses a relatively narrow area of the two-dimensional plate, we sought to evaluate the effect of meconium on this marker of fetal pulmonic maturity. Fig. 1 is a two-dimensional chromatogram with a mature L/S ratio and a high concentration of phosphatidylglycerol. In Fig. 2, the diffuse pattern of meconium interferes with the appropriate region for analysis of not only the L/S ratio but also phosphatidylglycerol. In Fig. 3, a distinct spot of phosphatidylglycerol can be discerned despite the presence of meconium. When meconium-stained amniotic fluid is obtained on amniocentesis, the reliability of the L/S ratio and the differentiation and quantitation of phosphatidylglycerol will vary on an individual basis. Careful review of the chromatogram may permit an accurate assessment of pulmonic maturity in a certain percentage of cases. However, if the requisite area of the chromatogram is

An analysis of the relationship of amniotic fluid shake test titers and the subsequent fetal lung maturity as evinced by the development of the respiratory distress syndrome (RDS) has been conducted. Over a four-year period, 131 amniotic fluid samples were tested within 48 hours of delivery. RDS was diagnosed in 16 infants. When the shake test was positive at a 1:2 dilution, one child developed a mild case of RDS (2.3%). If the test was postivie at a 1:4 dilution, none developed RDS. RDS occurred in 15% of the cases with a positive test at a 1:1 dilution and in 30% of the cases with a negative test. This test has proved to be an excellent screening method for predicting fetal lung maturity if it is positive at 1:2 or greater. If the result is positive at a 1:1 dilution, or negative, other methods must be used for assessment. Its advantages are its rapidity, simplicity, and low cost.