Hay's test
{{Short description|Chemical test used to detect the presence of bile salts in urine}}
Hay's test, also known as Hay's sulphur powder test, is a chemical test used for detecting the presence of bile salts in urine.{{cite book|author=D M Vasudevan|title=Textbook of Biochemistry for Medical Students|url=https://books.google.com/books?id=nQz8AAAAQBAJ&pg=PA350|year=2013|publisher=JP Medical Ltd|isbn=978-93-5090-530-2|page=350}}
Procedure
Sulphur powder is sprinkled into a test tube with three millilitres of urine and if the test is positive, the sulphur powder sinks to the bottom of the test tube. Sulphur powder sinks because bile salts decrease the surface tension of urine.{{cite book|author=Ashok Kumar J|title=Textbook of Biochemistry for Nurses|url=https://books.google.com/books?id=nZWijk31Kx0C&pg=PA208|date=1 January 2007|publisher=I. K. International Pvt Ltd|isbn=978-81-89866-45-7|page=208}}{{cite book|author=Harsh Mohan|title=Pathology Practical Book|url=https://books.google.com/books?id=x3n3cNOSH5AC&pg=PA169|date=30 November 2012|publisher=JP Medical Ltd|isbn=978-93-5090-266-0|page=169}}{{cite book|author=Dandekar|title=Practicals And Viva In Medical Biochemistry|url=https://books.google.com/books?id=s9HEoJquruwC&pg=PA47|date=1 January 2004|publisher=Elsevier India|isbn=978-81-8147-025-6|page=47}}{{cite book|author=Chary|title=Practical Biochemistry for Medical and Dental Students|url=https://books.google.com/books?id=n52SyUqERrUC&pg=PA20|date=1 January 2004|publisher=Jaypee Brothers Publishers|isbn=978-81-8061-233-6|page=20}}