Stool Parasite and Ameba Test: How to Give a Sample and How to Read the Result

Short Answer

Intestinal parasites do not pass into the stool every day or in the same amount; a single sample can miss a parasite. According to the 2017 guideline of the Turkish Society of Clinical Microbiology Specialists (KLİMUD), 3 samples should be examined within 10 days, preferably every other day. An "ameba" seen under the microscope cannot be distinguished from the harmless Entamoeba dispar. The US Centers for Disease Control and Prevention (CDC) recommends PCR and antigen tests for this distinction. A normal result reads "no parasites seen"; rely on the laboratory comment in your report.

How does it appear in your report?

• Test names: It may appear as "Stool parasites," "Parasites in feces (native-Lugol)," "Stool microscopy," "Giardia antigen," or "Entamoeba histolytica antigen."
• Normal result: "No parasites seen" or "Negative" is written.
• Positive result: The name of the parasite and the stage seen are written. For example, "Giardia intestinalis cyst" or "E. histolytica/E. dispar trophozoite."
• Ameba line: According to KLİMUD, if the diagnosis was made only by staining, the two species are reported together as "E. histolytica/E. dispar." A separate species name can be reported only with an antigen or molecular test.
• Quantity: Some parasites are reported as "few," "moderate," or "many." According to KLİMUD, "few" means at least 2 per 10 immersion (oil immersion) fields, "moderate" 3–9, and "many" 10 or more.
• Cells: Leukocytes, erythrocytes, Charcot-Leyden crystals, and yeast cells may also be added to the report.
• e-Nabız: In e-Nabız (Türkiye's national health record app), the "My Tests" section lists the result with its reference value; out-of-range results are colored.

Normal value and reference range

Examination	Sample plan	Normal result	Source
General parasite examination	3 samples within 10 days, preferably every other day	No parasites seen	KLİMUD 2017
Suspected Giardia or E. histolytica	Up to 6 samples within 14 days	No parasites seen	KLİMUD 2017
Giardia antigen test	At least 2 samples	Negative	KLİMUD 2017
Pinworm (cellophane tape)	In the morning before washing, at least 3–4 days in a row	No eggs seen	KLİMUD 2017, CDC
CDC recommendation	3 samples 2–3 days apart	No parasites seen	CDC DPDx

A reference range covers 95% of healthy people; about 1 in 20 healthy people may fall slightly outside the range. This rule is for numerical tests. In a parasite examination, the result is either "seen" or "not seen."

According to KLİMUD, there should be at least 24 hours between samples. The sensitivity of antigen tests varies by method. For Giardia, sensitivity of 96–99% has been reported for ELISA tests and 81% for card tests.

What does it mean if it is high?

In this test the result is not a number but "parasite seen" or "not seen." If a parasite was reported, the possibilities, from common and harmless to serious, are as follows:

• Species that do not cause disease: These include Entamoeba coli, Entamoeba hartmanni, Endolimax nana, and Iodamoeba bütschlii. According to KLİMUD, these species do not require treatment. They only show that food or drink contaminated with feces has been consumed.
• "E. histolytica/E. dispar" (ameba) report: The two species cannot be told apart under the microscope. According to the CDC, E. dispar generally does not cause disease. An antigen test or PCR is needed to identify the disease-causing E. histolytica.
• Blastocystis: Whether it causes disease is debated. KLİMUD recommends ruling out other causes before considering it a cause of diarrhea.
• Giardia intestinalis: It can cause yellowish, greasy, foul-smelling, and watery stools. Your doctor makes the treatment decision.
• Pinworm (Enterobius): According to the CDC, the most typical complaint is anal itching that worsens especially at night. The female worm lays her eggs around the anus; eggs are rarely found in stool. That is why the cellophane tape test is more suitable.
• Worm eggs and segments: Ascaris eggs or tapeworm segments may be seen in the stool or in the container.
• Parasites that need special staining: Parasites such as Cryptosporidium and Cyclospora require acid-fast staining. They may be missed in a routine examination.
• True ameba infection (E. histolytica): It can cause bloody, mucus-containing diarrhea. Rarely it causes a liver abscess; in this case parasites are often not seen in the stool.

What does a negative result mean? A single negative result does not show that there are no parasites. According to KLİMUD, a negative antigen test also does not rule out low numbers of parasites or other parasites.

Read together with

• "Ameba" + no symptoms: It is often the harmless E. dispar or another species. If needed, the doctor distinguishes them with antigen testing or PCR.
• "Ameba" + bloody, mucus-containing diarrhea: Bacterial dysentery is also considered; a stool culture is requested. Growth of Salmonella, Shigella, or Campylobacter in the culture is a critical value.
• Negative microscopy + positive Giardia antigen: According to KLİMUD, the antigen can be detected regardless of whether the parasite is being shed into the stool. Your doctor interprets the result together with your symptoms.
• Parasite + high eosinophils on the complete blood count: The doctor may investigate worm-type parasites in more detail.
• Fever, right upper abdominal pain + negative stool: A blood antibody test may be requested to look for an amebic liver abscess. According to the CDC, the antibody test is positive in about 95% of extraintestinal amebic disease.
• Bloody diarrhea + inflammatory bowel disease: KLİMUD emphasizes that detecting E. histolytica is important in these patients. The treatment decision is made with the relevant specialist.

Preparing for the test

• Container: Use a clean, dry, wide-mouthed container with a screw cap. A walnut-sized sample (20–40 g), or 15–25 mL for watery stool, is enough.
• Keep it uncontaminated: Urine or water must not mix with the stool. Do not take the sample from toilet paper.
• The right part: Take it from the part that looks bloody, mucus-containing, or purulent. This increases the chance of finding parasites.
• Time: Watery stool should be examined within 30 minutes, soft stool within 1 hour, and formed stool on the same day. If a fresh examination will be done, do not put the sample in the refrigerator.
• Medications: According to KLİMUD, no antacids, antidiarrheal drugs, mineral oil, barium, or bismuth should have been taken in the last 10–14 days. The CDC recommends waiting 2–3 weeks after antibiotics. Do not stop your medications on your own; discuss the timing with your doctor.
• Colonoscopy and barium X-rays: If one was done recently, tell the laboratory. According to the CDC, the effect of barium and bismuth lasts 7–10 days.
• Cellophane tape test: In the morning, before showering and going to the toilet, the tape is pressed onto at least 3–4 different areas around the anus and then stuck onto a slide. According to KLİMUD, the test is repeated at least 3–4 days in a row.
• Swab: According to KLİMUD, parasite examination is not performed on a stool sample taken with a swab.

Which doctor, which test?

• Person without symptoms in whom a harmless species was seen: Family physician. Treatment is generally not needed.
• Prolonged diarrhea, gas, abdominal pain, weight loss: Family physician or gastroenterology. A three-sample examination and Giardia antigen may be requested.
• Bloody, mucus-containing diarrhea: A doctor the same day. Stool culture and E. histolytica antigen or PCR are requested.
• "Ameba" report: Infectious diseases or family physician. It is appropriate to distinguish the species with antigen testing or PCR before treatment.
• Nighttime anal itching in a child: Pediatrics or family physician. A cellophane tape test is performed.
• Watery diarrhea in an immunocompromised person: Infectious diseases. Special staining or an antigen test for Cryptosporidium may be requested.

In Türkiye

• National standard: The National Microbiology Standards (UMS, 2014) of the Turkish Ministry of Health define stool parasite examination, amebiasis, and Giardia in separate procedures.
• Specialist society guideline: KLİMUD's 2017 guideline on Gastrointestinal System Samples describes the number of samples, storage conditions, and report wording in detail.
• Overdiagnosis of ameba: In a Turkish study published in Mikrobiyoloji Bülteni in 2022, 546 bloody or mucus-containing stool samples were examined. On direct microscopy, ameba was suspected in 36.3% of samples. In the 49 samples that remained suspicious on staining, the ELISA test was always negative; E. histolytica was not found by PCR either.
• Mandatory reporting: According to KLİMUD, E. histolytica, Giardia intestinalis, Cryptosporidium, and Trichinella spiralis are agents that laboratories must report. The laboratory reports them to the Provincial Health Directorate.
• Critical value: According to the Ministry's procedure, growth of Salmonella, Shigella, or Campylobacter in a stool culture and C. difficile toxin are critical values.
• Time to result: According to KLİMUD, a written result should normally be given within 16–72 hours.

When should you seek emergency care?

• If you have bloody diarrhea together with fever or severe abdominal pain, go to the emergency department the same day.
• If there are signs of fluid loss such as reduced urination, dizziness, or a dry mouth, seek care without waiting, especially for children and older adults.
• If there is confusion or fainting, call 112 (the emergency number in Türkiye).
• If fever and right upper abdominal pain occur together, see a doctor the same day.
• If the laboratory has called you about a critical value for a stool culture, do what you are told without delay.

Related tests

• Lab Test Guide: all tests
• How to read a complete blood count (CBC)
• When should liver enzymes be taken seriously?
• CRP, sedimentation rate, and procalcitonin: inflammation tests

What changed? (October 2026)

• New page. It is consistent with the KLİMUD 2017 Gastrointestinal System Samples guideline and the 2014 National Microbiology Standards.
• The ameba distinction was written according to CDC DPDx recommendations and the findings of the 2022 Turkish study.

Sources

• Klinik Mikrobiyoloji Uzmanlık Derneği (KLİMUD). Klinik Örnekten Sonuç Raporuna Uygulama Rehberi: Gastrointestinal Sistem Örnekleri. November 2017. https://www.klimud.org/uploads/content/Gastrointestinal%20Sistem%20%C3%B6rnekleri.pdf (accessed October 2, 2026)
• Republic of Türkiye Ministry of Health, Public Health Institution of Türkiye. Ulusal Mikrobiyoloji Standartları: Bulaşıcı Hastalıklar Laboratuvar Tanı Rehberi (Volumes I–III; table of contents in Volume II). 2014, Publication No. 934. https://hsgm.saglik.gov.tr/depo/birimler/mikrobiyoloji-referans-laboratuvarlari-ve-biyolojik-urunler-db/Dokumanlar/Rehberler/UMS_LabTaniRehberi_Cilt_2.pdf (accessed October 2, 2026)
• Tortop S, Koyuncu Özyurt Ö, Öngüt G et al. İshalli hastaların dışkı örneklerinde Entamoeba histolytica saptanmasında kullanılan yöntemlerin değerlendirilmesi. Mikrobiyol Bul 2022;56(4):682-691. https://doi.org/10.5578/mb.20229606 (accessed October 2, 2026)
• Centers for Disease Control and Prevention. DPDx: Stool Specimens – Specimen Collection. Reviewed 2016. https://www.cdc.gov/dpdx/diagnosticprocedures/stool/specimencoll.html (accessed October 2, 2026)
• Centers for Disease Control and Prevention. DPDx: Amebiasis. Reviewed 2019. https://www.cdc.gov/dpdx/amebiasis/index.html (accessed October 2, 2026)
• Centers for Disease Control and Prevention. DPDx: Enterobiasis. Reviewed 2019. https://www.cdc.gov/dpdx/enterobiasis/index.html (accessed October 2, 2026)
• Republic of Türkiye Ministry of Health, General Directorate of Health Services. Karar Sınırı (Eşik Değer), Kritik Değer (Panik Değer) ve Ölçüm Birimlerinin Harmonizasyonu Prosedürü. 22.09.2020. https://dosyamerkez.saglik.gov.tr/Eklenti/15143/0/karar-siniri-esik-deger-kriek42009846pdf.pdf (accessed October 2, 2026)
• Republic of Türkiye Ministry of Health. e-Nabız Kullanım Kılavuzu V2.1. 31.05.2025. https://enabiz.gov.tr/document/User_Manual.pdf (accessed October 2, 2026)