Gmelin's test

Gmelin's test is a chemical test used for detecting the presence of bile pigments in urine. It is named after Leopold Gmelin, who introduced the test.^[1][2][3] Five millilitres of urine is slowly added to five millilitres of concentrated nitric acid in a test-tube. Different coloured rings between the two layers are visible if bile pigments are present as they are oxidised to various chemical products.^[4][5] Nitric acid is used as the oxidising agent.^[6] Blue, green and violet rings are seen if bilirubin is present.^[7] Gmelin's test is not sensitive so a positive result always indicates the presence of bile pigments but a negative result does not exclude the presence of small quantities of bile pigments.^[8]

References

1. Erwin Kuntz; Hans-Dieter Kuntz (11 March 2009). Hepatology: Textbook and Atlas. Springer. p. 11. ISBN 978-3-540-76839-5.
2. John Daintith; Derek Gjertsen (4 March 1999). A Dictionary of Scientists. Oxford University Press. p. 216. ISBN 978-0-19-280086-2.
3. John Daintith (12 December 2010). Biographical Encyclopedia of Scientists, Third Edition. CRC Press. p. 295. ISBN 978-1-4200-7272-3.
4. Srinivas B Rao. Practical Biochemistry for Medical Students. Academic Publishers. p. 56.
5. Dandekar (1 January 2004). Practicals And Viva In Medical Biochemistry. Elsevier India. p. 47. ISBN 978-81-8147-025-6.
6. D M Vasudevan (2013). Textbook of Biochemistry for Medical Students. JP Medical Ltd. p. 279. ISBN 978-93-5090-530-2.
7. Malhotra (1 January 2003). Practical Biochemistry for Students. Jaypee Brothers Publishers. p. 46. ISBN 978-81-8061-109-4.
8. A.C. Croftan. Clinical Urinology. Рипол Классик. p. 123. ISBN 978-1-275-01265-3.