Stool Examination

Stool Examination

Stool Examination, Man consumes food for life, a certain part of it becomes part of the body, it is absorbed in the digestive system in the stomach and intestines, and after that, the rest of the waste remains, is excreted through the excretory system. Which is called stool.

Physical examination of stool:


Under normal conditions, the color of stool is brown, this color is due to Stercobilinogen, a pigment that is excreted with the stool. Indigestion in children causes green stools. If there is blood in the stool, it turns red, if blood is coming from the intestines, it turns red, and if blood comes from the stomach, it turns black. Jaundice causes yellow stools. Sometimes the color of medicines also comes in the stool, like the use of steel causes black stool.

Obtaining a stool sample:

For a stool test, a small amount of stool is placed in a clean, open-mouthed bottle and sent to the laboratory. The sample should be sent to the laboratory immediately after collection. Care should be taken when obtaining the sample not to include urine. The minimum volume of stool should be 5 ml.

General stool examination:

Usually, when the stool is examined, it contains the following.

  • PUS
  • FAT
  • EGGS
  • R.B.C
  • W.B.C
  • PH

Stool composition:

This refers to the consistency of the stool, how soft the stool is under normal conditions, not too hard. Blood or pus in the stool is a symptom of the disease, very thin watery diarrhea like cholera. Blood and eggs in the stool mean dysentery.


Usually, there are no parasites in the stool, small or round or tape-like worms in the stool are a sign of parasites. They can be of various diseases.


The pH of the stool is 7 to 8. If there are intestinal bacteria in the stool, the pH becomes acidic, and if the excess of stool is due to intestinal parasites, the pH of the stool becomes basic.

Presence of blood:

Two methods are adopted to determine the presence of blood in the stool which is as follows.
The benzidine test
Orthothallidone test

Benzidine Test:

If the amount of blood in the stool is 10 ml, it turns the color of the stool black, less than this, the color does not change with blood, so the test is done. R.B.C contains Hemoglobin on the breakdown of R.B.C oxidizes dihydrogen on the beam side and oxygen is released. This blue color makes the test positive.


For the test, a small amount of stool is taken, it is placed in a test tube and a solution is prepared with normal saline. Now one milliliter of hydrogen oxide is added to it. If a blue color appears, the test is positive, otherwise, it is negative. A positive test means that there is blood in it.

Orthothallidone Test Procedure:

A small amount of faces is taken and mixed with saline to make a solution inside the test tube. Now, orthodontic reagent is added to it. Will be.

  • Dissolve 2 grams of sodium perborate in 100 ml of water.
  • Dissolve 2 grams of Orthothallidone in 100 ml of acetic acid before use to prepare the reagent by mixing the two equally.

Microscopic examination:

A microscopic examination of the stool is also done.

Direct method:

For this, a glass slide is taken and a drop of normal saline is added to it, another slide is taken and 2% iodine solution is added to it. Now the part of the stool sample which has blood or pus on it is mixed on both sides with the help of a suture and a cover slip is placed on it and it is seen under the microscope at low power. And then it is looked at with higher power and various objects are found inside it like CYST, OVA, any moving amoeba, etc. Also, meat particles, hair fat, etc can be seen in the faces.

Stool Examination

Method of concentration:

Drugs used in this method are ether and formalin.

  • This method is used when the direct method cannot observe OVA or parasite.
  • This method is used for observation when OVAs are very few and cannot be seen by the direct method.

In this formalin kills the parasite and its nature does not change and they are visible. A 15ml conical tube is taken for this. 2 ml of feces is added to this, mixed with 3 ml of normal saline, and further diluted to 15 ml of normal saline to prepare the solution. This is centrifuged at 1500 RPM, the supernatant is discarded, the contents of the bottom flask are mixed with an additional 15 ml of normal saline and centrifuged again, the supernatant is clarified, and the sediment settles. Ten milliliters of formalin is added to the material and it is shaken for 5 minutes and centrifuged at 15RPM.

  • The lower part contains parasites.
  • There is a layer of formalin.
  • A layer of waste particles is formed.
  • An ether layer is formed on top.

Now leave the A layer and discard the rest. Slides of normal saline and iodine are prepared with this material and observed microscopically. OVA and CYST may now be observed.

Causes of stool discoloration:

Black Color:

  • If the stool is dark, one of the reasons is bleeding from the intestines.
  • Due to the use of iron (Iron) stool color can be dark.

Like clay:

  • One of the reasons for this may be a blockage of the hepatic duct.


  • Bleeding from the intestines can cause the stool to be red and contain fresh blood
  • Hemorrhoids can cause fresh blood in the stool.
  • Eating beetroot can cause red stools.

Excretion of mucus in stool:

  • It may be due to dysentery.
  • Ulcerative colitis can cause hives.

Worms and eggs in stool:

The following worms and eggs may be present in the stool during the examination.

  • Ent – Amoeba Histolytica
  • Giardiasis
  • Belin T. Dam Collie
  • Hook Worm
  • Entrobios Vermicular
  • H. Nana

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