Sign in →

Test Code TBSP Mycobacterium tuberculosis Complex Species Identification, PCR, Varies

Infectious


Ordering Guidance


This test should be used to identify the species within the Mycobacterium tuberculosis complex from a known M tuberculosis complex isolate.

 

For identification of M tuberculosis complex from isolate growth, order CTBID / Culture Referred for Identification, Mycobacterium and Nocardia, Varies.

 

For rapid identification of M tuberculosis complex directly from a specimen, order MTBRP / Mycobacterium tuberculosis Complex, Molecular Detection, PCR, Varies or MTBXS / Mycobacterium tuberculosis Complex, Molecular Detection and Rifampin Resistance, PCR, Sputum.



Shipping Instructions


1. For shipping information see Infectious Specimen Shipping Guidelines.

2. Place specimen in a large infectious container and label as an etiologic agent/infectious substance.



Necessary Information


Specimen source and suspected organism identification are required.



Specimen Required


Specimen Type: Mycobacterium tuberculosis complex isolate growing in pure culture

Supplies: Infectious Container, Large (T146)

Container/Tube: Growth on solid slant media, eg, Middlebrook 7H10, 7H11 and Lowenstein Jensen; growth in broth medium, eg, Mycobacteria Growth Indicator Tube, 7H9 broth BACT/ALERT MP or VersaTREK

Specimen Volume: Isolate with visible growth on solid media; if broth is sent, 3 mL or more of broth culture

Collection Instructions:

1. Bacterial organism must be submitted in pure culture, actively growing. Do not submit mixed cultures.

2. Place specimen in a large infectious container and label as an etiologic agent/infectious substance.

Additional Information: If subculture to Middlebrook agar medium is needed to ensure purity, turnaround time for results may be delayed.


Secondary ID

607364

Useful For

Determining the species of a Mycobacterium tuberculosis complex culture isolate

Additional Tests

Test ID Reporting Name Available Separately Always Performed
RTBSP Id, Mtb Speciation, PCR No, (Bill Only) Yes

Testing Algorithm

When this test is ordered, species identification will always be performed at an additional charge.

Method Name

Real-Time Polymerase Chain Reaction (PCR)

Reporting Name

M tuberculosis species ID, PCR

Specimen Type

Varies

Specimen Stability Information

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

Reject Due To

Agar plate
Mixed culture		 Reject

Clinical Information

This assay provides a species-level identification of microbiologic culture isolates previously identified to be a member of the Mycobacterium tuberculosis complex. Species level identification can be important for patient care or for epidemiologic investigations. For example, the species-level identification of Mycobacterium bovis bacillus Calmette-Guerin (BCG) can assist with identification of disseminated infections following use of the vaccine as an adjuvant during chemotherapy.

Reference Values

Not applicable

Interpretation

This assay can differentiate the most common species within the Mycobacterium tuberculosis complex, which are, M tuberculosis, Mycobacterium bovis, Mycobacterium bovis bacillus Calmette-Guerin (BCG; the vaccine strain), Mycobacterium canettii, Mycobacterium caprae, Mycobacterium microti, and Mycobacterium pinnepedii. This assay cannot distinguish Mycobacterium africanum from Mycobacterium mungi so if that result is obtained, the organism will be reported as M africanum/M mungi.

Cautions

Only isolates of Mycobacterium tuberculosis complex should be submitted and they must be in pure culture. Nontuberculous mycobacteria should not be submitted. Mixed cultures will result in a delay because the M tuberculosis complex organism must be isolated prior to performing the polymerase chain reaction assay.

 

This assay has not been verified for the direct detection of M tuberculosis complex from clinical specimens. It is intended for use on microbiologic culture isolates already identified as M tuberculosis complex.

Supportive Data

Type strains of Mycobacterium tuberculosis complex members were tested using the species identification polymerase chain reaction (PCR) assay and all were identified correctly. Type strains tested were M tuberculosis ATCC 27294, Mycobacterium bovis ATCC 19210, M bovis BCG ATCC 101472, Mycobacterium africanum ATCC 25240, Mycobacterium microti ATCC 19422, Mycobacterium caprae ATCC BAA 824, Mycobacterium pinnipedii ATCC BAA 688.

 

In addition, a clinical isolate of Mycobacterium canettii, identified by whole genome sequencing at the New York State Department of Health Wadsworth Center, was tested and confirmed to be M canettii by the M tuberculosis complex species identification PCR assay.

 

As part of the verification of this assay, 78 M tuberculosis complex isolates with the species identified at a reference laboratory were tested using the species identification PCR assay. All 78 isolates were correctly identified to the species level.

 

Table. Species reported by reference laboratory

LC 480 PCR results

 

M tuberculosis

M bovis

M bovis BCG

M africanium

M tuberculosis

53

 

 

 

M bovis

 

4

 

 

M bovis BCG

 

 

14

 

M africanium

 

 

 

7

 

Although the species identification test can be used only for mycobacterial isolates already identified as M tuberculosis complex, 159 other Mycobacterium species isolates were tested to determine whether any nontuberculous mycobacteria would be positive in the test. No nontuberculous mycobacteria were positive in the M tuberculosis complex species identification PCR assay.

Clinical Reference

Fitzgerald DW, Sterling TR, Haas DW. Mycobacterium tuberculosis. In: Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Elsevier; 2020:2985-3021

Method Description

The method uses real-time polymerase chain reaction on the LightCycler 480 platform with Mycobacterium tuberculosis complex-specific primers coupled with fluorescence resonance energy transfer probes to differentiate the members of the complex to the species level. The probes target specific regions of difference (RD) within the M tuberculosis complex genome. Detection of the presence or absence of these RD allows for differentiation of the species within the M tuberculosis complex.(Halse TA, Escuyer VE, Musser KA. Evaluation of a single tube multiplex real-time PCR for differentiation of members of the Mycobacterium tuberculosis complex in clinical specimens. J Clin Microbiol. 2011;49:2562-2567; Warshauer DM, Salfinger M, Desmond E, and Lin S-Y G. Mycobacterium tuberculosis complex. In: Carroll KC, Pfaller MA, Landry ML, et al, eds. Manual of Clinical Microbiology. 12th edition, ASM Press; 2019:576-594)

 

The RD's expected for each species within the M tuberculosis complex are shown in the table below. "+" indicates the region is present and "-" indicates the region is absent.

 

Expected RD signature patterns

RD1

RD4

RD9

RD12

RD9-2

Mycobacterium tuberculosis

+

+

+

+

+

Mycobacterium bovis

+

-

-

-

+

Mycobacterium bovis BCG

-

-

-

-

+

Mycobacterium africanum

+

+

-

+

+

Mycobacterium canettii

+

+

+

-

+

Mycobacterium caprae

+

+

-

-

+

Mycobacterium microti

-

+

-

+

+

Mycobacterium mungi

+

+

-

+

+

Mycobacterium pinnepedii

+

+

-

-

+

Day(s) Performed

Monday through Friday

Report Available

7 to 14 days

Specimen Retention Time

Subculture: 1 year

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

87150

LOINC Code Information

Test ID Test Order Name Order LOINC Value
TBSP M tuberculosis species ID, PCR 94576-6

 

Result ID Test Result Name Result LOINC Value
TBSP M tuberculosis species ID, PCR 94576-6