Two drops of iron(III) chloride are added to a test tube with distilled water. After mixing, it is divided into two parts. Add one millilitre of gastric juice in one test tube and the same volume of distilled water in the other test tube, which is acting as a control. The test tube with the gastric juice turns yellow in the presence of lactic acid due to the formation of ferric lactate.
- Sood (2006). Textbook of Medical Laboratory Technology. Jaypee Brothers Publishers. p. 444. ISBN 978-81-8061-591-7.
- K. Bhattacharya & G.K. Chakraborty; Ganendrakumar Chakravarti. A Handbook of Clinical Pathology. Academic Publishers. p. 205. ISBN 978-81-87504-85-6.
- Dandekar (1 January 2004). Practicals And Viva In Medical Biochemistry. Elsevier India. p. 33. ISBN 978-81-8147-025-6.
- Yadav (1 January 2003). Comprehensive Practical and Viva in Biochemistry. Jaypee Brothers Publishers. p. 84. ISBN 978-81-8061-210-7.