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Test Code LAB3576 Microsporidia species, Molecular Detection, PCR, Varies

Important Note

This test replaces Microsporidium exam (MCOP) at UVM Medical Center.

Useful For

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

Reporting Name

Microsporidia PCR

Specimen Type

Varies


Ordering Guidance


For specimens other than feces or urine, MTBS / Microsporidia Stain, Varies should be ordered since it will detect other microsporidia not targeted by this assay.



Necessary Information


Specimen source is required.



Specimen Required


Submit only 1 of the following specimens:

 

Preferred:

Specimen Type: Unpreserved feces

Supplies:

-Stool container, Small (Random), 4 oz (T288)

-Stool Collection Kit, Random (T635)

Container/Tube: Fecal container

Specimen Volume: 5 g

 

Specimen Type: Preserved feces

Supplies:

-ECOFIX Stool Transport Vial (Kit) (T219)

-Stool Collection Kit, Random (T635)

Container/Tube: ECOFIX preservative

Specimen Volume: 5 g

 

Specimen Type: Urine

Container/Tube: Sterile container

Specimen Volume: 5 mL

Collection Instructions: Mid-stream, clean-catch, suprapubic aspirates and catheterization collections are acceptable. Submit in a clean, sterile container free from preservatives. The first portion of the voided urine (first void) is also acceptable.


Specimen Minimum Volume

Feces: 1 g
Urine: 0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Refrigerated (preferred) 7 days
  Ambient  7 days
  Frozen  7 days

Reject Due To

Urine containing preservatives
Prostate secretions and samples
Feces in preservatives other than ECOFIX		 Reject

Clinical Information

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, which can infect the conjunctiva, respiratory tract, and genitourinary system. Human infections have been reported most frequently in patients with AIDS but can also occur in other patients who are immunocompromised, 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, E bieneusi and Encephalitozoon species, and not microsporidiosis due to other species.

 

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

Reference Values

Negative

Interpretation

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 E bieneusi and Encephalitozoon species in the specimen. Still, this 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

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 E 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 polymerase chain reaction (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 5000 target DNA copies/mcL 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 Enterocytozoon bieneusi at 1 to 2 dilutions lower than microscopy.

Clinical Reference

1. Didier ES, Weiss LM: Microsporidiosis: Not just in AIDS patients. Curr Opin Infect Dis. 2011 Oct;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. 2014 Apr;27(2):371-418

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

Method Description

Nucleic acid is extracted from feces and urine using the automated MagNA Pure bead-based system (Roche Molecular Systems). The extract is then transferred to individual self-contained capillary cuvettes for amplification. The LightCycler is a self-contained automated instrument that amplifies and monitors the development of target nucleic acid (amplicon) after each cycle of polymerase chain reaction (PCR).

 

The DNA target for PCR assay is the 18S ribosomal RNA gene of Enterocytozoon bieneusi, Encephalitozoon intestinalis, Encephalitozoon hellem, and Encephalitozoon cuniculi.

 

This assay utilizes 2 primers and 2 probes, which are specific for E bieneusi and 3 primers and 2 probes specific for Encephalitozoon species. The specific base pair DNA target sequence is first amplified by PCR using the target-specific primers. Amplicon is then detected during melting curve analysis using fluorescence resonance energy transfer probes, which utilizes one hybridization probe with a donor fluorophore, fluorescein, at the 3' end and a second hybridization probe with an acceptor fluorophore, at the 5' end. Fluorescence is produced when the 2 probes anneal to the target sequence in close proximity to one another. The LC-Red 670 emits a measurable and quantifiable light signal at a specific wavelength when E bieneusi is present, and the LC-Red 610 emits a measurable and quantifiable light signal in the presence of Encephalitozoon species.(Bernard PS, Reiser A, Pritham GH: Mutation detection by fluorescent hybridization probe melting curves. In: Meuer S, Wittwer C, Nakagawara K, eds. Rapid Cycle Real-Time PCR: Methods and Applications. Springer; 2012:11-20)

Day(s) Performed

Tuesday through Friday

Report Available

2 to 4 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

87798

LOINC Code Information

Test ID Test Order Name Order LOINC Value
LCMSP Microsporidia PCR 94332-4

 

Result ID Test Result Name Result LOINC Value
MSPS Specimen Source 31208-2
36744 Encephalitozoon species 94333-2
36745 Enterocytozoon bieneusi 94334-0

NY State Approved

Yes

Method Name

Real-Time Polymerase Chain Reaction (PCR)/DNA Probe Hybridization

Forms

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-Microbiology Test Request (T244)

-Gastroenterology and Hepatology Test Request (T728)