Preferred test for detection of Pneumocystis
Real-Time Polymerase Chain Reaction (PCR)
Varies
This test should always be performed in conjunction with fungal culture; order FGEN / Fungal Culture, Routine.
Specimen must arrive within 7 days of collection; specimens older than 7 days will be rejected.
Specimen source is required.
Question ID | Description | Answers |
---|---|---|
SRC63 | Specimen Source |
The high sensitivity of amplification by polymerase chain reaction requires the specimen to be processed in an environment in which contamination of the specimen by Pneumocystis species DNA is unlikely.
Preferred Specimens: Pleural, respiratory (eg, bronchoalveolar lavage [BAL], bronchial washing, sputum), or fresh tissue
Acceptable Specimens: If no fresh specimen is available, digested respiratory specimens treated with N-acetyl-L-cysteine-sodium hydroxide (NALC/NaOH) are acceptable (eg, BAL, bronchial washing, respiratory fluid, sputum, or tracheal secretion)
Submit only 1 of the following specimens:
Preferred
Specimen Type: Body fluid
Sources: Pleural
Container/Tube: Sterile container
Specimen Volume: 1 mL
Additional Information: Only fresh, non-NALC/NaOH-digested body fluid is acceptable.
Specimen Type: Respiratory
Sources: BAL, bronchial washing, tracheal secretions, or sputum
Container/Tube: Sterile container
Specimen Volume: 1 mL if only PCR ordered or 3 mL if PCR ordered with smear and culture
Specimen Type: Tissue
Sources: Respiratory
Container/Tube: Sterile container
Specimen Volume: 5-10 mm
Collection Instructions:
1. Submit fresh tissue.
2. Keep tissue moist with sterile water or sterile saline
Acceptable
Specimen Type: NALC/NaOH-digested respiratory specimens
Sources: BAL, bronchial washing, respiratory fluid, sputum, or tracheal secretion
Container/Tube: Sterile container
Specimen Volume: 2 mL
Collection Instructions:
1. Submit digested specimen treated with NALC/NaOH.
2. Clearly indicate on container and order form that specimen is a digested specimen.
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.
Body fluid or nondigested respiratory specimen: 0.5 mL; Fresh tissue: 5 mm; NALC-NaOH-digested specimen: 1 mL
Body fluid other than pleural fluid Blood Bone Nonrespiratory tissue Bone marrow Organ tissues other than lung Paraffin-embedded tissue Specimen in anaerobe vial or viral transport medium Feces Swab Tissue in formalin fluid Urine | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Varies | Refrigerated (preferred) | 7 days | |
Frozen | 7 days |
Preferred test for detection of Pneumocystis
Pneumocystis pneumonia is an important cause of opportunistic infection in patients who are immunocompromised, particularly those with HIV. The causative agent, Pneumocystis jiroveci, cannot be cultured in vitro, and, therefore, laboratory detection has historically relied upon microscopic identification directly from patient specimens using fluorescent stains or antibodies. Stains often lack sensitivity and require expertise on the part of the reader to differentiate Pneumocystis jiroveci from staining artifacts and other fungi. This real-time polymerase chain reaction assay provides a sensitive and specific detection of Pneumocystis from bronchoalveolar lavage fluid and other respiratory specimens.
Not applicable
A positive result indicates the presence of Pneumocystis DNA.
A negative result indicates the absence of detectable
Test results should be used as an aid in diagnosis and should not be considered diagnostic in themselves. The literature indicates that Pneumocystis can cause asymptomatic colonization of healthy individuals and those who are immunocompromised. Therefore, test results should be correlated with patient symptoms and clinical presentation.
A negative result does not rule out the presence of Pneumocystis or active disease because the organism may be present at undetectable levels.
1. Senecal J, Smyth E, Del Corpo O, et al: Non-invasive diagnosis of Pneumocystis jirovecii pneumonia: a systematic review and meta-analysis. Clin Microbiol Infect. 2022 Jan;28(1):23-30. doi: 10.1016/j.cmi.2021.08.017
2. Apostolopoulou A, Fishman JA: The pathogenesis and diagnosis of Pneumocystis jiroveci pneumonia. J Fungi (Basel). 2022 Nov 5;8(11):1167. doi: 10.3390/jof8111167
3. Fishman JA. Pneumocystis jiroveci. Semin Respir Crit Care Med. 2020 Feb;41(1):141-157. doi: 10.1055/s-0039-3399559
Nucleic acids are extracted using the MagNA Pure LC Instrument (Roche). The extract is then amplified using the LightCycler real-time polymerase chain reaction (PCR) platform (Roche). The detection of amplicon is based on fluorescence resonance energy transfer (FRET), which utilizes hybridization probes. The presence of the specific organism nucleic acid is confirmed by performing a melting curve analysis of the amplicon.(Arcenas RC, Uhl JR, Buckwalter SP, et al: A real-time PCR assay for detection of Pneumocystis from bronchoalveolar lavage fluid. Diagn Microbiol Infect Dis. 2006 Mar;54(3):169-175)
Monday through Sunday
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.
87798
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
PNRP | Pneumocystis PCR | 89996-3 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
SRC63 | Specimen Source | 31208-2 |
81698 | Pneumocystis PCR, Result | 89996-3 |
24188 | Special Information | 48767-8 |
24189 | Report Status | No LOINC Needed |