Lugol’s Iodine Solution
- Lugol’s iodine is mainly used in the wet preparation of stool.
Ingredients of Lugol’s Iodine Solution:
- Iodine powder = 5 grams.
- Potassium iodide = 10 grams.
- Distilled water = 100 mL.
Procedure for Lugol’s Iodine Solution preparation:
- Dissolve the potassium iodide in the distilled water.
- Add iodine crystals slowly and keep shaking the container (test tube) until these are dissolved.
- Filter the resulting solution.
- This is the stock solution.
- For the working solution:
- Dilute the stock solution 1:5 with distilled water.
- You can use this working solution for 2 to 3 weeks and make a new working solution.
Procedure for stool examination:
- Make a direct wet smear.
- A small portion of the stool is mixed with a drop of saline and Lugol iodine solution.
- Place the cover slip on it.
- The smears should be thin so you can read the newspaper under the slide.
- Check for the amoebae and flagellates. Also, look for cysts.
Result of Lugols iodine:
- Lugol iodine will stain the cyst of amoebae and other protozoa.
- Iodine stain will show the details which can not be seen by saline preparation.
- Trophozoites are rapidly killed by iodine and may not be identifiable.
- When the iodine crystals disappear from the bottom of the bottle, the stock solution is no longer to be used.
- Now you need to replace the working solution.
Questions and answers:
Question 1: What is the use of Lugol's iodine?
It will differentiate ova and cyst.
Question 2: What will happen to trophozoites by Lugol's iodine?
Trophozoites will be killed by the Lugol's iodine solution.