Lab Test

Stain, Isospora

Isospora Stain

Test Codes





At least 2 weeks should elapse following barium administration before collection of the specimen.

Specimen Collection Criteria

Collect: Random stool specimen or duodenal aspirate placed in a transport vial with SAF preservative.

  • Fill the vial until the fluid level reaches the red fill line.
  • Unpreserved stool must be placed in SAF within 1 hour of collection.  

Physician Office/Draw Specimen Preparation

Maintain specimens in SAF preservative at room temperature (20-25°C or 68-77°F) prior to transport.

Preparation for Courier Transport

Transport: Stool in SAF preservative, at room temperature (20-26°C or 68-78.8°F).

Rejection Criteria

  • Solid or formed specimens.
  • Rectal swabs.
  • Specimens in leaking or soiled containers.
  • Specimens containing oil or urine.
  • Specimens that contain toilet water.
  • Specimens received in diapers.
  • Specimens collected within 7 days of the patient taking a laxative.
  • Specimens collected following a soap suds enema.
  • Stools containing barium from a previous radiological procedure.
  • Specimens collected within 14 days following antibiotics.
  • Unpreserved stool greater than 1 hour past collection.
  • Specimens in PVA.
  • Frozen specimens.
  • Testing will not be performed on more than one specimen collected per patient within a 24 hour period.


Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 1 hour (Unpreserved)
Room Temperature (20-25°C or 68-77°F): 7 days (Preserved)
Refrigerated (2-8°C or 36-46°F): 7 days (Preserved)
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Room Temperature (20-26°C or 68-78.8°F): 7 days


Royal Oak Microbiology Laboratory
Dearborn, Farmington Hills, Grosse Pointe, Taylor, Trenton, Troy and Wayne sent to Royal Oak Microbiology Laboratory for testing. 


Monday – Friday, 7:00 am – 3:30 pm.
Results available within 24 hours.

Reference Range

No Isospora seen.

Test Methodology

Concentration, stain, microscopic examination.


Demonstration of oocysts in feces or in duodenal aspirates or finding developmental stages of the parasite in biopsy specimens of the small intestine is diagnostic of infection.

Clinical Utility

This assay aids in the diagnosis of isoporiasis.

Clinical Disease

Isoporiasis is caused by Isospora belli, a coccidian protozoan. The most common presenting symptom of isosporiasis is protracted watery diarrhea. Clinical manifestations are similar to those caused by Cryptosporidium and include abdominal pain, anorexia, and weight loss. Infection can be life threatening in immunocompromised patients, particularly those with AIDS. Fever, malaise, abdominal pain, nausea, and headache have all been reported (1). The disease may persist for months or years. Oocysts may be shed irregularly, so multiple stool specimens are recommended for testing (2).


Humans are the only known host for I. belli. Frequency of this parasite, especially in asymptomatic persons, is unknown. Infection is more common in tropical and subtropical than in temperate climates and in areas of poor sanitary conditions (1). Infection can involve both adults and children, and compromised and immunocompetent individuals. Disease is usually self-limiting in the immunocompetent (2).

Incubation Period

Estimated to be 8-14 days, based on a small number of persons who had laboratory exposure to the organism (1).


Human infection probably occurs by the oral-fecal route. Oocysts are resistant to most disinfectants and may remain viable for months in a cool, moist environment (1).


  1. Garcia, L.S. 2007. Intestinal Protozoa (Coccidia Microsporida) and Algae. Diagnostic Medical Parasitalogy, 5th edition. ASM Press. Washington, D.C.
  2. Novak-Weekley, S., and A.L. Leber,. 2015. Cystoisospora, Cyclospora, and Sarcocystis. Jorgensen, J.H., et. al. (eds.), Manual of Clinical Microbiology, 11th ed. ASM Press, Washington, D.C.

CPT Codes

87207, 87015.


Last Updated


Microtainer® and Vacutainer® are registered trademarks of Becton, Dickinson and Company.
UroVysion® is a registered trademark of Abbott Laboratories. ThinPrep® is a registered trademark of Hologic, Incorporated.