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Test Catalog

Test ID: LCMSP    
Microsporidia species, Molecular Detection, PCR, Varies

Useful For Suggests clinical disorders or settings where the test may be helpful

Detection of Enterocytozoon bieneusi and Encephalitozoon species in fecal and urine specimens to support the clinical diagnosis of microsporidiosis

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Microsporidia are highly specialized fungi that cause a wide variety of clinical syndromes in humans. The most common microsporidia are Enterocytozoon bieneusi and Encephalitozoon intestinalis, which infect the gastrointestinal tract and cause a diarrheal illness, and Encephalitozoon cuniculi and Encephalitozoon hellem that can infect the conjunctiva, respiratory tract, and genitourinary system. Human infections have been reported most frequently in patients with AIDS, but also can occur in other immunocompromised patients, including solid organ allograft recipients and, sporadically, immunocompetent hosts. Less commonly, other microsporidia such as Vittaforma corneae and Brachiola species can cause disseminated or organ-specific disease. This assay detects only the most common microsporidia, Enterocytozoon bieneusi and Encephalitozoon species, and not microsporidiosis due to other species.

 

See Parasitic Investigation of Stool Specimens Algorithm and Laboratory Testing for Infectious Causes of Diarrhea in Special Instructions for other diagnostic tests that may be of value in evaluating patients with diarrhea.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Negative

Interpretation Provides information to assist in interpretation of the test results

A positive result indicates the presence of Enterocytozoon bieneusi and Encephalitozoon species DNA and is consistent with an active or recent infection. Since microsporidia DNA may be present in feces or urine in the absence of clinical symptoms, results should be correlated with clinical presentation.

 

A negative result indicates absence of detectable DNA from Enterocytozoon bieneusi and Encephalitozoon species in the specimen, but does not always rule out ongoing microsporidiosis since the organism may be present at very low levels or may be sporadic.

 

Other tests to consider in the evaluation of a patient presenting with acute or chronic watery diarrhea include cultures or specific assays for bacterial, viral, and parasitic pathogens.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

This test only detects DNA from Enterocytozoon bieneusi and Encephalitozoon species and does not detect the less common microsporidia. These 2 genera are the most common causes of intestinal and renal microsporidiosis.

 

While this assay is designed to detect symptomatic infection with Enterocytozoon bieneusi and Encephalitozoon species, it may detect asymptomatic carriage and should only be used for patients with a clinical history and symptoms consistent with microsporidiosis.

Supportive Data

In a study using 205 clinical specimens and 254 spiked specimens, the Microsporidia PCR assay had 90% to 100% sensitivity and 100% specificity in all specimen types accepted for this assay. The limit of detection is between 500 to 5,000 target DNA copies/mL of specimen. When 10-fold dilutions of fresh stool specimens containing Enterocytozoon bieneusi spores were tested by both PCR and microscopy, PCR showed significantly greater sensitivity, with the ability to detect at Enterocytozoon bieneusi at 1 to 2 dilutions lower than microscopy.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Didier ES, Weiss LM: Microsporidiosis: Not just in AIDS patients. Curr Opin Infect Dis 2011;24 (5):490-495

2. Nagpal A, Pritt BS, Lorenz EC, et al: Disseminated microsporidiosis in a renal transplant recipient: case report and review of the literature. Transpl Infect Dis. 2013 Oct;15(5):526-532

3. Verweij JJ, Stensvold CR: Molecular Testing for Clinical Diagnosis and Epidemiological Investigations of Intestinal Parasitic Infections. Clin.Microbiol. Rev. April 2014;27:371-418

4. Wolk DM, Schneider SK, Wengenack NL, et al: Real-time PCR method for detection of Encephalitozoon intestinalis from stool specimens. J Clin Microbiol 2002 Nov;40(11):3922-3928

Special Instructions Library of PDFs including pertinent information and forms related to the test