(b) Lugol's iodine.
Iodine (powdered crystals) ................................ 2.5 gm
Potassium iodide ............................................... 5.0 gm
Distilled water .................................................... 50.0 ml
Mix the potassium iodide in distilled water, add the iodine, and mix
well. Store in stoppered brown glass bottles. Just before use, dilute
1:5 with distilled water. The stock solution is stable for three weeks;
the working solution is stable for 10 days.
(c) Procedure. Place one drop (approximately 0.05 milliliter) of iodine
solution on the other end of the slide used for the saline preparation. Using an applicator
stick, place a small portion of feces (approximately 0.1 milligram) in the iodine drop and
mix until the suspension becomes homogenous.
(3) Merthiolate-Iodine-Formaldehyde (MIF). Besides being used as a
preservative, MIF is a suitable stain for wet smears. The reagents are prepared in a
different concentration than the one described for the fixative.
(a) Stock reagents.
1 Merthiolate-formaldehyde (MF)--solution A.
Formaldehyde (saturated) ........................... 15.0 ml
Tincture of merthiolate (Lilly 1:1,000)........... 75.0 ml
Store in a stoppered brown glass bottle.
2 Lugol's iodine solution (I)--solution A.
Iodine crystals (powdered) ........................... 5.0 gm
Potassium iodide ......................................... 10.0 gm
Distilled water .............................................. 100.0 ml
Dissolve the potassium iodide in water. Add the iodine crystals
slowly and shake until dissolved. Filter and store in a brown
bottle. This solution is only stable for three weeks.
(b) Working reagent. Add 9.0 milliliters of Solution A to 1.0 milliliter of
Solution B immediately prior to use. For smaller or larger volumes, decrease or increase
both components proportionately. Mixing the two solutions too far in advance causes a
precipitate to form, thus reducing the staining capacity.
MD0841
2-40