Definition

Stool, or feces, is the waste product of digestion that is expelled through the anus after food undergoes absorption and decomposition in the digestive tract. Although considered waste, stool can provide valuable insights into the health of the digestive system. Routine stool tests can reveal conditions such as inflammation, allergies, malabsorption, infections, and even malignancies affecting the digestive system. Conducting these tests in a laboratory is simple, affordable, and quick.

Routine stool tests can be performed on both children and adults. They are particularly useful in diagnosing digestive issues in children, such as diarrhea, food allergies, and malabsorption disorders. These tests help detect diseases affecting the digestive system and provide insights into the health of the liver and pancreas. They are frequently used to identify pathogens causing diarrhea in both children and adults, such as bacteria, viruses, or parasites, thereby assisting doctors in diagnosing diseases more effectively.

Stool tests include three types of analysis: macroscopic (visual), microscopic (using a microscope), and chemical. These analyses can help identify abnormalities or diseases affecting the digestive system, liver, or pancreas.

Indications

Doctors typically recommend routine stool tests when there is a suspicion of certain medical conditions in adults or children, such as:

• Infections in the digestive tract that may be caused by bacteria, viruses, worms, or parasites, and are often characterized by symptoms like diarrhea, bloody or slimy stools, loose stools, nausea, vomiting, and fever, particularly in children.
• Inflammatory digestive diseases, such as ulcerative colitis, which involves inflammation of the large intestine and is common in adults, or Crohn's disease.
• Food allergies in infants and children, this often includes milk protein allergies.
• Malabsorption disorders that involve difficulties in absorbing sugars, fats, and other essential nutrients in the digestive system.
• Bloody stools, and there is a suspicion of malignancy.
• Evaluating the effectiveness of ongoing treatments.

Contraindications

There are no specific medical conditions that prevent a routine stool test from being conducted. However, it is essential to inform your doctor about all medications you are currently taking. Certain medications can influence the test results and may not accurately reflect the actual condition of your digestive system.

Preparation Prior to Test

To ensure accurate results, several preparations must be made before undergoing a routine stool test. These include:

• Inform your doctor about any medications or drugs you are currently taking. Certain medications may need to be temporarily discontinued to avoid affecting the test results.
• Let your doctor know if you have recently traveled to specific regions, particularly 1–2 weeks prior to experiencing gastrointestinal symptoms like diarrhea. This information can help identify potential bacterial causes of diarrhea, aiding in diagnosis.
• Women who are menstruating or experiencing bleeding from other parts of the body should postpone the test, as this can interfere with the accuracy of the results.
• Avoid consuming specific foods, such as spicy dishes or those containing chili, 2–3 days before the test to prevent any influence on the test results.

Test Procedure

The stool test involves two parts, collecting a stool sample and the subsequent analysis performed by laboratory personnel. Follow these steps to collect a proper stool sample:

• Wash your hands thoroughly before beginning the sample collection.
• Prepare the stool collection tube provided by the lab staff. Avoid frequently opening the tube cap before collecting the sample, as this increases the risk of contamination.
• Use a bedpan, clean plastic sheet, or a sterile container placed in the toilet to collect the stool.
• Ensure the stool does not fall into or come into contact with the toilet to prevent contamination from other germs.
• Once collected, use the attached spoon on the tube cap to transfer a portion of the stool into the provided tube.
• Fill the tube with the stool sample until it reaches at least one-third of the container's capacity.
• Close the tube tightly to prevent spillage or contamination.
• Place the sealed tube in a clean plastic bag.
• Wash your hands thoroughly again after completing the collection process.
• Submit the stool sample to the laboratory for further analysis.

Normal and Abnormal Values

Macroscopic Test

This test visually evaluates the stool's physical characteristics, including color, consistency, shape, and the presence of mucus. Normally, the stool is yellow-brownish, influenced by the bilirubin produced by the body. For infants and children, green stool is also considered normal. Stool consistency should be soft, smooth, and sausage-shaped. Mucus should be minimal or absent.

Meanwhile, stool colors such as white, grayish, pitch black, or red are unusual. Irregular stool shapes or watery, porridge-like consistency are also abnormal. Excessive reddish mucus is an indicator of potential issues.

Microscopic Test

Under a microscope, components such as leukocytes, epithelium, erythrocytes, worm eggs, and parasites are assessed. Normally, leukocytes (white blood cells) and erythrocytes (red blood cells) should not be present. Epithelium can be present in small amounts. Stool should not contain worm eggs, parasites, or protozoan cysts (e.g., E. Histolytica).

Meanwhile in abnormal stool, there will be presence of leukocytes, erythrocytes, or large amounts of epithelium is considered abnormal. Detecting 1–2 worm eggs, parasites, or protozoan cysts also indicates an issue.

Chemical Test

Chemical test evaluates the fat and sugar content in the stool and measures its pH level. Normally, stool contains less than 6 grams of fat over a 24-hour period. Values exceeding this indicate an abnormal condition.

Sugar levels in stool are typically below 0.25 mg/dL, while levels exceeding 0.5 mg/dL are considered abnormal. A range of 0.25–0.5 mg/dL may suggest carbohydrate absorption disorders.

The normal pH of stool ranges from 7.0–7.5. A pH below 7.0 indicates acidity, while a pH above 7.5 indicates alkalinity. For breastfed infants, a mildly acidic stool pH is normal.

Results and Recommendations (Follow-up Tests)

Macroscopic Test

If the stool test shows abnormalities in its macroscopic characteristics, such as red stool, it may indicate blood in the stool caused by digestive tract bleeding due to bacterial infections like Shigella or Salmonella, or parasitic infections such as hookworm and protozoan infections like E. Histolytica. Black stool or melena often signals bleeding in the upper digestive tract, such as the stomach, which is commonly associated with conditions like gastritis. On the other hand, grayish-white stool suggests the absence of bilirubin, often due to a blockage in the bile duct. In adults, this is commonly caused by gallstones, while in infants and children, it may indicate biliary atresia, a condition involving the absence of the gallbladder or bile duct.

If the stool consistency is watery or soft with irregular shapes and contains a significant amount of mucus, it may indicate diarrhea with mucus. This condition often points to a disturbance in the digestive system, particularly the intestines, and is frequently caused by inflammation or infections from bacteria, viruses, fungi, or parasites. Such cases are especially prevalent among infants and children.

Microscopic Test

Abnormal results in the microscopic analysis of stool, such as the presence of leukocytes, suggest bacterial infections or inflammation in the intestines. Conversely, leukocytes are typically absent in stool when the infection is viral or parasitic. The presence of erythrocytes in stool could result from bacterial infections, as well as worm or parasitic infestations.

Additionally, if worm eggs or protozoan cysts are found, it definitively indicates a digestive tract infection caused by these organisms.

Chemical Test

Chemical test abnormalities, such as increased fat or sugar levels in stool, suggest a failure to absorb these nutrients properly. This condition may be linked to diseases like pancreatitis, severe diarrhea due to infection, or certain genetic disorders.

Stool acidity may result from lactose absorption issues, as seen in lactose intolerance. Conversely, alkaline stool often points to intestinal inflammation.

Routine stool tests provide valuable information for diagnosing digestive system disorders. However, additional laboratory tests, such as occult blood tests, stool cultures, abdominal ultrasounds, or complete blood counts, are often needed to confirm the exact cause of digestive issues.

Consult the Right Doctor

If the results of your routine stool test are abnormal, consult a general practitioner or an internal medicine specialist. A thorough medical history, symptom evaluation, and physical examination by the doctor are essential for determining the underlying cause. For children with abnormal stool test results, it is crucial to consult a pediatrician promptly. Early diagnosis and treatment can prevent complications and ensure that the child’s growth and development are not affected.

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