All of the following are predictive tests for PIH except

Shake test or bubble test This is a useful bed side test rapidly performed with a fair degreeof accuracy.The test is based on the ability of pulmonary surfactant to form a foamor bubble on shaking which remains stable for atleast 15 mts.Increasing dilutions of amniotic fluid are mixed with 96%ethanol ,shaken for 15 s and inspected after 15 mts for the presenceof a complete ring of bubbles at the meniscus.If it is present the test is possitive and indicate maturity of fetal lungs D.C.DUTTA&;S TEXTBOOK OF OBSTETRICS,Pg no:111,7th edition