Skip navigation

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

URL of this page: //

Smear of duodenal fluid aspirate

Smear of duodenal fluid aspirate is an exam of fluid from the duodenum to check for signs of an infection (such as giardia or strongyloides). Rarely, this test is also done in a newborn to check for biliary atresia.

How the Test is Performed

A sample is taken during a procedure called an esophagogastroduodenoscopy (EGD).

How to Prepare for the Test

Do not eat or drink anything for 12 hours before the test.

How the Test will Feel

You may feel like you have to gag as the tube is passed, but the procedure is most often not painful. You can get medicines to help you relax and be free of pain. If you get anesthesia, you cannot drive for the rest of the day.

Why the Test is Performed

The test is done to look for infection of the small bowel. However, it is not often needed. In most cases, this test is only done when a diagnosis cannot be made with other tests.

Normal Results

There should be no disease-causing organisms in the duodenum. Normal value ranges may vary slightly among different laboratories. Talk to your provider about the meaning of your specific test results.

What Abnormal Results Mean

The results may show the presence of giardia protozoa, the intestinal parasite strongyloides, or another infectious organism.


The risks of this test include:

  • Bleeding
  • Perforation of (poking a hole in) the gastrointestinal tract by the scope
  • Infection

Some people may not be able to have this test because of other medical conditions.


Other tests that are less invasive can often find the source of the infection.

Alternative Names

Duodenal aspirated fluid smear


Dent AE, Kazura JW. Strongyloidiasis (Strongyloides stercoralis). In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 321.

Diemert DJ. Nematode infections. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 335.

Mathisson BA, Pritt BS. Medical parasitology. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 65.

Mathison BA, Pritt BS. Parasitology. In: Rifai N, Chiu RWK, Young I, Burnham CAD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. St Louis, MO: Elsevier; 2023:chap 88.

Siddiqi HA, Rabinowitz S, Axiotis CA. Laboratory diagnosis of gastrointestinal and pancreatic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA : Elsevier; 2022:chap 23.

Review Date 5/6/2022

Updated by: Michael M. Phillips, MD, Emeritus Professor of Medicine, The George Washington University School of Medicine, Washington, DC. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

Related MedlinePlus Health Topics